Final notice recieved when account paid

on 1 December i paid my account, and on 3 December i received a final notice , on the final notice they put a call centre number , however no one in the call centre can help, they give the account number department number and no one in the accounts department works as their phones just ring. The email on the final notice also bounces back as invalid email. <br> So now do i get cut off because no one in the call centre can help me or do i hope that they can see my payment , how does one get a final notice delivery charge reversed , as my account was paid before the notice was printed.<br> <br> REALLY CAN SOMEONE EITHER HELP ME , OR ANSWER THE PHONES IN THE RIGHT DEPARTMENT THAT CAN HELP ME !!!!!