Virgin Media cannot fix problem after 14 months since signing up with them

I moved from BT and Sky to VM in February 2023. I ported my line line number I had with BT to VM. However, calls made from the EE network to my VM landline, (ported from BT) cannot get through. Calls from EE receive a BT voicemail message. Callers from other networks, O2, Vodafone etc get through. The problem lies with porting and EE are not routing calls to the VM network. A call to EE say that VM need to contact EE and request to have the 'date fill' for the VM number removed from there switch as they are not routing it correctly. This request as it is a network configuration, can only come from the gaining porting provider, VM. This is backed up from OFCOM. VM are responsible for the porting and to ensure that it has been successfully completed. Despite me having complained every month since February 2023, VM have done nothing. They keep passing the issue back to me to retry. VM CANNOT FIX THIS ISSUE, IT IS BEYOND THERE CAPABILITIES. They have passed this to the porting team, to network engineers, to telephony engineers, to the IT engineers, back to complaint's, been escalated to management, absolutely a waste of time. I have been in contact with OFCOM and raised a complaint with the Ombudsman, and they are a waste of time as they have not chased this enough. As soon as the contract is up I'm switching back to BT.