pathetic MTN

last wee.k agreed to a 2 year telphonic upgrade as I was on a month to month account. I was told i could reverse if within 10days. I have emailed the company that sold me the upgrade asking to reverse the deal and have had no response. I have been to the local MTN store and they wont help. I have made numerous calls to 135 and I just get the runaround and the calls just eventually drop. This must be the worst service a company can give and to think that I have been a customer for over 20 years...fed up