Allocation of Payment

My account was handed over to MBD last year May 2023 by MTN,they called me almost every other second day to make a payment and settle my MTN account and they even emailed me statements monthly which reflected the amount i owed and in the statement there are three banking accounts which are Absa,Fnb and Standard bank, on the 15th November 2023 when i got my bonus i called them to ask that which account number must i use to make a payment because they were three account numbers on the statement,they said i should use Standard bank account number,i then made the payment i emailed them the proof of payment,then they said they will send it to their accounts department for them to allocate it,they then responded on the 22nd to say that the account number i used does not belong to them,that they will send to MTN for them to verify if the account belongs to them...mind you i am there one who is busy making follow up they are not calling me to inform me about the progress.....i have tons of emails i sent to them trying to make a follow up,the last email they said i should call my bank and check were the payment went to,my bank also said they cant trace as the account number is a Standard bank account number my bank is Capitec, Mind you I used the account number that was on their statement to make the payment, i triple checked before making any payment, now they are telling me that the account does not belong to them,My Name is now blacklisted,i cant take credit anywhere...I regret taking that contract phone with the most useless service provider which is MTN, MBD IS WORSE