Telkom The worst company to deal with

I'm fed up with Telkom!!!!!! They Blacklist me for money I DO NO OWE. From 2017 I'm struggling to sort this account out, with NO results. I have cancelled my contract within the 7 days which they stipulated, but still they deducted the money every month from my account. I have give back my router still sealed, but they want to charge me! I want my name of the blacklist NOW!!!!!