cancellation of contract

In 2017 on Wed, Mar 29, at 11:16 AM requested a cancellation on my Telkom mobile number *** I never received any feedback, I was advise to send a mail to *** which I did but the was no reply from Telkom I recently found out that I’m blacklisted and it’s messing up my credit scores I spoke to many agents regarding the cancellation but never got any progress on how the matter is being handled i need urgent assistance with this