Home movers no response, service agents cannot help

Hi all, looking for some help/advice. I recently moved home to a non-serviceable area and my service was disconnected. I have since had the final bill, which has been paid and that included a service disconnection fee. I was informed that if I sent evidence of my new address to homemovers@virginmedia.co.uk it would be validated in 24-72 hours and a credit would be arranged if the evidence was accepted. I sent this information on 16th October, no response, not even a mail NDR. I spent almost 80 minutes on the phone yesterday being passed between 7 agents plus a manager only to be told to send the same information to the same mail address and that it was a ‘back office’ function to who they had no means of contact. As a customer of over 20 years with no major issues until I had to leave I find this very disappointing, I would appreciate any  guidance the community could provide on a way forward.