Incorrect billing

I have a 5 gig Samsung Tablet with Telkom Mobile for R349, the contract expired in October. From November onward, Telkom is charging me R905 for November and December almost three times the original contract value. I've been trying to resolve the issue, however the store sends me to the call center and the call center sends me back to the store. I've been ping ponging between the two platforms however the problem hasn't been resolved. I'm honestly tired of running around trying to resolve an issue caused by Telkom. I just need this contract cancelled and Telkom is making it very hard to do so while charging me for nonsense. To make matters worse, the contract has been suspended however i'm still been charged. Why exactly am i supposed to pay for a non-existent services. I requested the contract to be cancelled at the end of November but because of the contract issues Telkom has not been able to resolve the issue. I am still waiting for the contract cancellation.