MTN contract led to incorrect bureau listing

I made a grave error in agreeing to extent my sim-only data contract with MTN in May 2025. A new debicheck was setup and approved for R139pm. However, MTN was not running this new debicheck and trying the older debit (deactivated and more expensive) which was not going through. I confirmed this with 135 agent who fixed the dc going forward. Then, I would be texted a link to pay the old rate and I would pay to stay connected. To my shock, MTN was flagging me on the bureau for their own mistake. MTN needs to refund me the overcharges and remove the missed payments on my profile. Another option is cancelling my contract - the incompetence is unreal. I have already sent 3 emails to Complaints team.