I would suggest that you'll both need to speak with Ombudsman Services if the forum staff can't sort this out. Unfortunately for VM, Ombudsman Services charge VM around £400 for a full adjudication (I used to work for a company who also used Ombudsman Services, I've a pretty sound idea of how it all works). And VM will be held at fault and have to sort of the free gift and compensation.
Now, if forum staff can't cut through the chaotic mess of marketing offer fulfilment (and it does seem that way), then can I suggest that they might think as an alternative having a word with the relevant people in VM to sort out a generous bill credit to the tune of the current market price of the TV in question plus say £70 that the ombudsman would certainly apply? That's potentially quick, resolves the matter for the customers who are currently being let down, takes the messed-up fulfilment process out of the equation, and most importantly for VM, avoids two lots of adjudication fees?