Cancel My contract PLEASE!!

Good Day, <br> <br> My Telkom Mobile data contract has come to the end of its two year period. Telkom said I should fill out a form and submit it to there cancellation department via email which I did In November. but my internet is still on this month meaning they going to bill me again end December which is what I DONT want because I never bugeted for that. What DONT YOU UNDERSTAND TELKO.. CANCEL MY CONTRACT. NEVER AGAIN!! You do not provide a quality service or even attempt to contact your clients whos contracts come to an end. You simply just carry on sending bills!