MTN badly affecting my credit rating

I cancelled my contract with MTN on 5 May 2021 and paid all the penalties that came with that. I received an SMS on 12 July that said that I needed to pay R224.00 (on my contract) otherwise my services will be stopped and that would affect my credit rating; I then sent an email to *** - which I never got a response to to date. I have just checked my credit score (20/09/2021) on ClearScore and it says that I have an account with MTN that is in arrears by R407!!!! Please fix this MTN, you are putting a dent on my financial fitness.