This is why I told you you could summon an entity to help you. If you protect I think it's possible to not undo it to you and how will she know afterall?
I do not intend to imply anything by this: But when you say you know the witch, do you mean physically? Because on the other hand this post sounds like you say you saw the 'witch' by somewhat 'magickal' means. As in you 'see' them through the results of 'trying to hurt you' as you put it. Also the 'we spoke on the astral plane' bit.
You should familiarize yourself with a spell before trying to perform it. Are all the involved sides real enough to be included in such a working? After all people put a lot of energy into spells. Nonetheless I respect all deities (you mentioned 'Hecate') given it is known that the proposed names aren't necessarily ultimate. Different pantheons can call the same deity by different names.
Hmm... this sounds like an interesting situation indeed. and I can see there are couple of possibilities that are going on here.
First, the possibility that this person and his/her mother are childish, spiteful people. It is one thing to attack to defend yourself. It is another to attack to gain justice. And yet another entirely to continually cause mischief and trouble beyond what is necessary to be spiteful. The downside is that if it is the latter of these, there isn't much you can do save to move on to other things and just ignore them entirely. I can't imagine that they would be able to put much power behind their workings with an immature mindset and the lack of Self-awareness that comes with it. The best way to defend yourself from such a situation is to stop feeding it your own power. by wondering and worrying and checking and protecting, you are committing attention and energy to their efforts, validating them, and helping to fuel the situation. Personally I find it likely that they are pretty unaware due to the odd threats actions, like attacking your crystals (which is silly), and apparently threatening to steal your book of shadows, as if it was the source of a person's magic or something. It is just a book and can be easily begun anew. Heck, losing it can sometimes even be a benefit as while you write a new one, you can pen it through your current level of experience, in effect updating the text and information and presenting an excuse to revisit the things you have already studied and learned to refine and clarify that knowledge. In the end you would lose nothing but a little time.
If this is the situation then I would suggest first doing a cleanse of yourself and your home, then do a severing of ties rite or ritual. It acts as a cutting of Karmic bonds to allow you to go your separate ways. Finally, offer a small blessing of peace and love to them as you see them off to their own journey, and continue to live content that you have no more connection or worry involving them. And even as they inevitably continue to try and affect you, recognize consciously that they have no power or influence over yourself or your home. After a while their attempts would become beneath your attention.
Another possibility is that they are simply not getting what they want from you. It looks like you have done a lot of work in the avenues of defense and forgiveness, but what about apology? have you actually expressed those words to them for the slight that occurred? A genuine apology goes a long ways in satisfying people with legitimate concerns. Even if that legitimacy comes from only knowing half the story. And often, it eventually leads to them following suit and apologizing as well once tempers calm and they have the chance to realize that they have been acting in an inappropriate way. But it won't happen, once again, so long as there is fuel being added to the fire. You lose nothing but pride by apologizing, and if it has not been done yet, it might be worth a try.
I have apologized, but I had to do it over a message instead of face to face as the person was very angry when I first tired to talk to them face to face. But they moved away before I was able to talk to them face to face, so if I could go to them and apologue in person, I would have. And when I say I know the witch, I mean physically. As they wanted me to teach them Wicca, such as rituals, spells, honoring the god and goddess and other things like that. While I don't know how strong the mother is, the person mentioned that their mother taught her some, and that the mother had told the person about the "bad things" about wicca, as in what not to do, and the dangers of it.
I think I understand. It sounds like you have done your part in the situation then, and by the way you have been talking, I can gather there there is a good degree of sincerity in that and also a measure of remorse.
It is indeed sounding to me like it may simply be time to consider separating yourself from them and their situation entirely and to start moving in a new direction. Committing more effort to apology and such would be a bit of a waste. To that end I think some sort of severing might be a valid solution. By separating yourself from them, they would lose connection to you. So even if they did send negativity after you, with no connection to follow it would have troubles actually finding its mark. So to speak.
I believe there are a few different ways you could go about this, depending on your own preferences and practice. As long as you create a formalized way of first representing yourself and the other people involved, then representing a connection binding you together as a group. Then formally and deliberately cutting yourself free from the representation, and so the situation and any energetic, emotional, or karmic ties that have resulted.
The trick is in being self-aware while doing it. Not cutting in anger or hatred. This isn't a harmful act. But instead, try to focus on forgiveness and release. The idea that you an release your bonds with a sense of love and conclusion. Return to them their energy. It doesn't belong to you anyways so why hold on to it? Their energy is theirs. Let them have it back. ^_^
A simple version would take some string and beads. Create your usual ritual setting or place of power, and focus on first representing the situation. Place a bead with intent of representing yourself at the center of a length of string. If you want, you can make it a set of three, or one string for each person involved including yourself, all of them a different color that you feel represents the quality of that person's energy. place a knot on either side to represent the force of contention, then place one other bead for each other person involved on either side of you.
Then, with an affirmation of self and a declaration of severing your ties, consciously and deliberately cut through the knots on either side of yourself, separating yourself from the others and their situation.
There should be other similar spells on the website, and of course there are ways you can modify this premise and idea to suit your style and knowledge. I have heard of people weaving beads or charms into a dreamcatcher/craft hoop like a spider web, and then cutting themselves free from the tangle. Others have followed up by re-tying the leftover string and beads together, and sealing the knot in wax to reaffirm the connection of the remaining people to each other with themselves being separate from it.
To me you still sound like you have never met this witch. So why don't you offer to 'teach them wicca'. It is what they want. About the mother I think she is not to be taken lightly if she has already taught about what not to do and gotten it right. But lastly if you have not met her and only spoken online as you claim to have apologized to her, then it is not as important
