Yet another contract renewal problem!

I am posting on this forum in desperation as like many others in this community I was offered to renew my existing contract (on 8th January 2025) at the same price for the same package for another 18 months. I accepted this online offer (for a few pounds more) and I was sent a contract summary sheet, a contact information sheet and an order summary from your web team. This contract has however never been applied to my account. I have been in contact with your retentions department on a regular basis since February and rolling credits have been agreed to bring my monthly bill to the correct agreed amount offered however the rolling credits department keep rejecting this request. The reasons given range from my account number/area reference being missing from the documents (this has since been added) to the order reference being incorrect (this was on the order summary generated by your web team). Yesterday (7th April) your retentions team advised that despite their best efforts of getting the agreed rolling credits applied (they have tried four or five times now) they had no other option but to pass my case to your deadlock department for resolution. I have today received an email saying my complaint is now resolved. Nothing has changed on my account so the complaint is NOT RESOLVED! Since January I have been billed almost double what what agreed which is not ok. Surely it is not acceptable for Virgin Media to offer me a new contract (which I accepted), send documents confirming the new contract but never apply it to my account? Please can someone help me with how to get this resolved once and for all? I am prepared to go to the Ombudsman with my complaint however I am already feeling exhausted by it all. Thank you.