This is theft

I had a telkom Tablet and data contract for R250 which I honoured to the end, at the end of the contract I went to the store(Highveld Mall branch) for an upgrade they told I me can't have it, I then went to apply with another service provider. after a year and one month I realised they was still deducting an amount of R99 with summed up to R1100 went to the branch(Highveld Mall) to find out what is going on. I asked the teller "since your said I do not qualify for upgrade or further contracts why are you still deducting from my account and with what contract do you have rights to deduct", she told me the best she can do is cancel the account. but still there was deductions in my account , I went back and she told me I must cancel online she gave me some steps to follow and I did only to find out there was no active account I have with Telkom . I went back to the branch she said she will cancel on the system and told me it was done but still Telkom deducts from my account even worse now they deduct scary amounts like R3500 and I get forced to reverse and this is ruining my credit score