Looks like forum staff haven't taken the hint, so let's help you with taking the matter to the industry adjudicator CISAS, to (a) get it put right, (b) refund the over-charging, and to (c) get the compensation you're reasonably entitled to for the initial incompetence and then dragging the matter out for months (we're talking around £150).
First step on the road to CISAS, have you made a formal complaint to VM and got a complaint reference, if so when was that? If you have already got a complaint reference over eight weeks old, then you're good to involve CISAS now. Don't keep waiting on VM, judging by your comments they've had months and repeated opportunities to sort this, but chosen not to.
If you haven't yet raised a formal complaint, do it now. Ask for a resolution of a, b & c above, wait and see if they offer that. If they don't then as soon as you get a resolution email or letter (likely to be a badly worded fob off) then you reply, rejecting it and asking for a deadlock letter. Once you've got the deadlock letter then you're clear to go to CISAS without waiting eight weeks.