The only thing you can do is disconnect yourself emotionally. You can write to her and ask her to hand the final papers in and state that you have given her everything for a clean break. Was she a difficult controlling person?

Lawyers are ridiculously expensive.

Keep the letter as proof of the facts.

Doing this is her way of keeping control, so, switch off thoughts of her do not over react or let her see you angry or hurt it will feed her control and let her know she is still pulling your strings.
Be calm, disinterested. Without giving her attention eventually she will become bored.