Have had the exact same problem, which I have been fighting since January this year.
Never signed up for Netflix, don't have TV through VM, but I started getting a bill. My process used to be: phone VM every month and fight for a credit for the next month, then phone Netflix and confirm that there was no account belonging to my email address (on the off chance that someone else had signed up), but I got tired of doing that. So I went to the ombudsman, who then formally escalated to Liberty Global. This seemed to resolve the issue, for 1 month. Now, I am getting higher bills again, as well as notifications that my previous bills were not settled in full - and the Netflix subscription is back on the bill.
So, I would suggest escalating via the ombudsman service and hope for the best.
I did see that VM has just notified its customers that because prices will go up with inflation, they will allow people to cancel without penalty. Let's see if that is an easy way out.
Wish I could offer you more conclusive help. Good luck!
