Bad service

I have a bad experience with Telkom, I had a 24 months data contract and they deducted even after when I realized it was over 24 months by 7 months then I reversed the money to be told I was suppose to come and cancel the contract which was not communicated and I believe I was binded with a signature for 24 months so who authorised after that ok I made arrangements and said I'll be able to pay 250, first month they took 250 the following month 434 how, as per who. I give up on this, why didn't they just stop the datas when I reversed the money as I didn't even notice as I had wifi in the house and at work so their ways of sales sucks I don't wna lie