Incorrect billings and still no refund

Was overbilled two months in a row and after querying this was told that I would be refunded, been getting sms confirmation that my queries have been resolved but still no refund and its been almost another month. Definitely cancelling my contract and moving to another service provider as Telkom service has become pathetic to say the least, poor communication, delayed feedback, empty promises etc etc etc and they must dare mention anything about cancellation terms and conditions as they have not kept their end of the deal by providing their clients with the service they expect.