Telkom Debits me over the stipulated amount over three months, and all they say is sorry this is as per terms and conditions!!

I signed up for a 2 new data contracts at Telkom close to the end of April. This was an uncapped LTE and 40/40 data contract which would have left me paying some figure around R1 300- 00 per month. The first month bill at the end of May they charged me around R3 000 and I assumed it was pro rata costs for the new contracts but the next months costs were even higher (R3 500). I then wen and queried and Telkom said there was a spend limit of R1500 on one contract and some amount on another. So when data ran out on the fixed data contract I would automatically start spending from this spend Limit. 1. I did not allocate this spend limit to myself and Telkom says its automatic 2. No one explained to me the existence of a spend limit when I signed up. The staff did not even say anything to me about it 3. Telkom is saying its my fault someone should have explained to me I cancelled the spend limit but unfortunately they had deducted for the month already and the next month bill after cancellation of spend limit was much higher at (R3800). So they roughly debited me about R10 000 in 3-4 months instead of something around R4000 . Telkom throws me back to shop and call center for this issue. The staff member who issued me this contract is know, and being protected because well, they have my money thanks to her