Contract cancellation

My husband has a contract with MTN and now it has elapsed we want to cancel the contract. We went to the branch in Brooklyn and we were told to contact customer care on 135 you will hold for over an hour. i have sent email to customer support and received the following reference number ***. till to date i haven't received any feedback yet we are expected to pay every month. You will only receive a call from MTN for upgrade purposes, but when you want to cancel no one is willing to assist. I'm going to take this up with CGSO.