
The trail of misery and havoc left behind by this shower of crooks and bandits is terrible. IVAs were made for people in your position. If you still have their letter, complain to the Office of Fair Trading. You might not think anything has happened, but they can't do anything unless they get the complaints to start off with, and a number of complaints might make them take notice of these con men and take up someone else's complaint, even if not yours.
It would be best to speak to preferably the supervisor of your IVA, or otherwise perhaps Myvesta to try and sort out the mess you are left with.
Hope everything turns out well.