What is there to fix, actually?
It sounds like a small job, so if any money is in the escrow (assuming it is a fixed price job), it might be best just to refund the client so you avoid getting a bad public review showing in your profile.
Art type of work is easy for these kinds of bad clients to dispute since the value can be very subjective, but your case seems pretty extreme and completely unprofessional as you mentioned. My sympathies.
The good thing is that you probably learned your lesson here:
I'm sorry to hear that your contract with your client is not working out. I can see that you have already submitted a dispute to our team. One of our disputes team members will update your ticket to assist you further.