Cancelled contract on bill

I had a contract with 8ta for one number and when I went for the upgrade, I was informed I'd have to get a new contract as the other expires in a week. The day I went to collect my new cellphone I submitted both the new contract forms, plus a cancellation form for the old contract. I asked that the \current"contract I had. Two months down the line I get an invoice with the old contract included. I try call the call centre and Nonhle can't help me. How can they find forms for 1 contract but not the cancellation? They were submitted together. Now she's making it my problem"