Unable to register account

I moved house, my old account was cancelled and a new one set up with a new account number and contract.

I get emails RE bills and my contract to the original account email address. If I sign into my account it shows me only the old contract information and the old bills, nothing about the new contract or account. 

Ive called support and have been told I need to register a new account with a new email address. Every time I do I am told that something went wrong. I have tried different browsers, reset the cache, different email addresses, everything. 

I called back and was told to just try again later. I have been trying to access my account details for over 4 months now and I cant. Calling support has not helped. 

I need this resolving asap.