Moved house but they are still charging me.

I have been on the phone with the call centre for over 35 minutes for a call I couldn't even get a reference number for. I moved house a month ago, I phoned you two months prior to tell you that I was moving and needed my facility moved. Reference number for that call:***. Today I received a bill stating that I owed for my previous property (which was not properly installed) as well as my current. WHY? Because I apparently didn't necessarily use the word \cancel."Now you tell me"