Online account issue

I joined on the 29th December, set up Virgin Media O2 id, downloaded app but cannot link my Virgin media account to it - I just get a message that my account is found but can’t be merged and to either try later or speak to us

I’ve tried on different days and still no joy, I rang and was told that it needed resetting and someone would call but nothing and that was 3 weeks ago nearly, is there another way to contact someone for help?