Contract Cancellation

I put in a request on the 18th of Feb 2015 to cancel my Telkom Internet 5 Promo contract, I then got a call from their 'Retentions department' and the lady I spoke to assured me that she is processing my cancellation request. I contacted Telkom on the 3rd of March to ensure my contract was indeed cancelled as my sim card was still active and to my Suprise NOTHING was done!! Today is the 23rd of March and my contract is still active, I keep getting promises that it will be cancelled. Spoke to their clueless managers at the call centre that does absolutely NOTHING, I mean how difficult can it be to cancel a contract that is on a month to month basis! I am disgusted by such service!! They keep telling me someone from retentions will contact me....I don't want to be contacted, I want my contract to be cancelled for crying out loud!!! I