Contract already expired NOT CANCELLED since Jan!

My MTN contract lapsed in January 2015 and I have been trying to formally cancel my contract with MTN. After several visits to different MTN branches to cancel the contract, I was informed to rather cancel the contract via the phone. I have spent countless hours on the phone, just waiting to speak to an agent! Finally, I got through to an agent on the 23rd of April who informed me that my contract will be cancelled after 5days (so 30 April 2015). Now I called them today - 6 May 2015 and I am told that the contract has yet to be cancelled because there is a backlog. How can there be a backlog to cancel a contract that is already lapsed? I do not wish to pay for this contract anymore! I keep paying every month for a contract I am not using anymore. So please, make sure my contract is cancelled IMMEDIATELY! I am not happy at all and will definitely not be signing up for another MTN contract. The process of cancelling a simple contract is full of admin, countless hours and MONEY SPENT! I do not want to spend an extra minute or time on this contract cancellation process anymore. So MTN please do your job ASAP.