I thought it had to be something simple. It may be worth logging into MyBT, and checking your recent usage since the fault was reported.
Do you still need the assistance of the moderation team?
Firstly, you'll find it's near enough impossible explaining the situation down the phone because it's so peculiar and completely off their script. The only way I managed to get it fixed was getting an engineer out and explain the situation to him.
It turned out that connections within my block of apartments accidentally got switched at the connection box. I had someone elses broadband, and they had mine.
If I remember rightly, if you test your phone line on the BT website it should pick up on some problems saying that they need to send someone out to check the lines. Calling the customer services for broadband will just result in them checking your connectivity, saying it's fine and that the problem is with your devices and then closing the ticket.
I hope this helps in some way. No one should go through the headache it caused me.