Separation and arrears

I have separated from my wife, this occurred in July/2018 and I moved out completely on Sep/2018.

Full ownership of the Virgin Media account, bills and running the account was supposed to be taken over by my ex. I requested this change with Virgin Media, they sent the form out, it was sent back and I was under the impression it was all completed.

Now we don't have a joint account, I am getting sent letters and emails chasing up arrears. On calling them I found out that the account had not been changed over and they are still waiting on completed forms.

I no longer have access to the house, have not been using the service for months.

My first port of call was to make sure that continued services did not persist and the bill they want gets larger. I went from pillar to post and eventually got someone in their cancellations team to issue an immediate disconnection. I became extremely frustrated with her because although I made it clear at least 3 times in the call with her that I was not on speaking terms with my ex, she kept pushing for me to "recommend" my wife for services in her name and we would both get vouchers. Her english was bad but she really wasn't getting that gaining vouchers was the least thing on my mind.

I was informed by the agent that the boxes need to be returned, something I can not do since I don't have access to the home and don't talk to my ex any more.

I pushed for them to chase both the arrears and the return of the equipment with my ex, they didn't want to do that, insisting it was my issue.

I have raised an online complaint with resolver.co.uk and am looking for a resolution that involves my ex picking up the arrears and sorting out return of the box. I am unsure if they will do this, but that is what I am looking for in a resolution.

It would be a different story if I never attempted to change ownership of the account, but not only did they agree to do it but they also told me that it would cost £20 to do, something I was not happy about but agreed to do it anyway. Surely, with all the effort I made to transfer the account, their seemingly limited efforts to live up to their side and get it changed that I have an argument of poor service and of passing the ball to them to take ownership of the arrears. (either to chase my ex or understand that they were not mine and write them off)

My plan is to wait to see what comes about with the complaint, meanwhile forward any letters or emails I get from Virginmedia to my ex, by post and insist that she deals with them (including both paying the amount owed and returning the equipment)

Virginmedia have no information as to my forwarding address.
I have no desire to pay the arrears but wonder if I dig my heels in if I am just opening myself up to getting multiple chase letters, it eventually getting passed to a debt agency and then having to argue with them, and added costs they decide to throw in, all the while taking chunks out of my credit file for not making payment.

Am I doing the right thing to resolve this?