Horrible Life Coach Saga Part 2

M previous life coach who pretended to be terminally sick now wants to finish the last two sessions she owes me that I prepaid her for back in March. Despite my trying to get in touch with her via email and by phone, she keeps putting off our last (2) sessions and I already paid her in advance for the sessions which is her policy. So I wrote her an email about 3 days ago (taking her up on her previous offer) requesting that she just refund me for the last 2 sessions which is about $500 versus trying to meet up. I have not heard anything from her yet. I am trying to put this in the model before I go all ape and show up at her office demanding my refund (that’s if she’s even there and her office hasn’t been closed down by the feds – who knows with her).

C Line: My previous life coach owes me money for 2 sessions that were never completed OR the refund amount for the 2 sessions.
T: I am thinking that she will NEVER pay me what she owes me OR make good on the sessions because it has been about one month since I have seen her and about one week since I last heard from her. (She never calls or text messages – only emails)
F: I feel angry, ripped off, taken advantage of and I feel like going after her legally.
A: Because it has only been one week since I have heard from her, I am going to wait one more week and see if she reaches out to me. Though I really don’t want to, I am trying to keep it together and not go ballistic inside of my head.
R: I am anxious – feel like all of this is un-resolved and can’t seem to move on.

I know that I should maybe just walk away from the $500 and take this as a bad lesson that I selected the wrong coach but some part of me feels that if I don’t do something about this, it will keep happening to other people. How do you follow the model without being a door mat? Any help or advice would be greatly appreciated.