Telkom
Cancellation of goods but still being billed

I toke a contract with Telekom for a samsung galaxy tab 3 and within 3 days was not happy with the product I toke it back and cancelled the tab3 within 7 days that's what the consultant told me then the end off the month I got a bill which I charge for the tab3 and are still charge for even if I went twice back to the shop for this problem and got case numbers I need my problem to be solved please ASAP, 1st case no is 7126949