Unhappy MTN customer

Disappointed customer.!!!! I cancelled my MTN contract In January 2024 only to be contacted in December that I'm owing mtn again???? . After numerous calls going to different departments and failing to get assistance.. I'm disappointed with their customer service my query has not been resolved till to date... I want my query to be resolved as I'm tired of going to the store and calling 135.. As it's of no assistance and this is affecting my ITC credit score.. MTN has let me down I won't go again to apply for any contracts,!!!!