Netflix Plan Change Declined but still being charged.

A couple of months ago I opted to upgrade my entertainment services to include Netflix standard (without ads). I’ve been billed two months consecutively for this, but I’ve received an email to say that:

“Virgin Media didn't approve your plan change because they need you to contact them to get your plan change approved.

We've moved you back to your previous plan for the moment, but please contact Virgin Media to resolve the issue.”

As a result, I appear still to be on the standard Netflix package with adverts despite paying for the service without ads.

Please advise?