USELESS SERVICE

In 2019 my contract end with MTN and I went from 24 months contract to month to month data package. In 2020 I Migrate to prepaid MTN request me to pay the settlement amount to cancel the which I did immediately my cell number was changed from contract to prepaid but I Have R705 on bill and its affect my ITC score .I phoned MTN 100 time I have send the proof of payments, the emails the dates. No one is bothered to action my query .Last month I got a call from NUDEBT that my account has been handed over to the collector . I don't believe MTN has Mangers