MTN and Mondo just incredibly poor

I am now getting really irate with Mondo and MTN. I was sold a contract which does not work on a mobile device, was then told the contract would be cancelled, but having followed up every week for a month, nothing has been done.

Promises made, but nobody ever comes back to me, I am now being billed for something I am not able to use... This is wholly unacceptable and must be resolved now.