Cancellation of contract

I have been a loyal customer of Telkom mobile for the past 6 years but now that I want to cancel my contract they are giving me the run around. I went to the store in Cresta and was told I cannot put in the cancellation request there, I need to send it via email. I did that and even phone into the call centre to confirm that they received my cancellation request but was told that they will not be able to see it and only when the contract finishes then can they see the request. Now that the contract has ended they are still giving me minutes and data and when I phoned in to confirm they say that my contract is now on a month to month as no cancellation request was sent in. This is such ****ty service from such a big service provider. I am now unable to use data as the SIM card is loaded and I cannot use it because they will charge me. Really expected better service from you guys.