Telkom SUCKS

I have cancelled my Telkom account in October 2017, throughout 2018 I on numerous occasions forwarded the cancelation document to Telkom online and visited their stores on multiple times. As of 2018 I started reversing their payments through my bank with proof that I sent the cancelation letter as well as the plethora of emails that was sent to them. Today I found out that the bank is invlating my intrest rate due to an outstanding Telkom account. How is it possible that Telkom keeps steeling my money and I get a bad credit rating.