So sorry to hear you are being mistreated.

Since it's online, why not block the person and go no contact?

Also, 2 other suggestions:

Read this blog: Baggage Reclaim Home - Baggage Reclaim with Natalie Lue I find it very helpful.

Also, do some inner work on yourself to find out why you tolerated the abuse. You could start at Codependents Anonymous for your country or online meetings worldwide: CoDA.org