Telkom contract cancelation

I am beyond disappointed in Telkom. I have been requesting for them to cancel this one contract i have finished paying for for months now, i initially went to a store in pavilion to request for an upgrade the guy there assisted me and told me my upgrade was done come month end telkom is still invoicing me for the old contract which i was under the impression that it was upgraded and i would no longer be charged for so now im being charged for this new contract which i thought was an upgrade and the old contract which they refused to upgrade and cancel, i can no longer afford to pay for something i didnt bugdet for which is not even my fault the guy at the store failed to do a simple upgrade and preted like he did.

The whole of telkom is failing to cancel a simple contract...i went again at the store to cancel the old contract and the insurance i had with it, i was assured by the lady at the store that the contract was canceled successfully and i even received an sms confirmation same with tbe insurance guys they sent me a confirmation email that it was canceled but im still receiving the invoice with the same charges. How hard can it be to cancel a damn contract or atleast answer my calls when i call you guys. Your customerservice sucks big time.