Bad service received from MTN

I have a data contract which was converted to Pay as you Go on 29/07/2021. It was at a zero- rated charge. On 30/06/2023 an amount of R205.00 was deducted from my bank account with the ref number for the same cell number. I went to the MTN shop at Festival Mall on 01/07/2023 to query this. The consultant confirmed that there should not have been a charge and I provided proof that MTN deducted this amount. I called 135 on Thursday, 06/07/2023 and was told that it was a billing query and that it will be investigated. I have sent 2 e-mails; one to complaints department and the other to their retentions department. I had to reverse it at my bank and charges were incurred. I received a SMS today from MTN to inform me that my service will be disconnected as I owe them this money, which is incorrect. This is a Pay as you go sim card hence, I am very disturbed that there is a charge which 2 consultants were unable to give me an explanation for. I am still waiting on a response and what the bill is for. This is unacceptable and very poor service from this service provider. I have requested for my banking details to be removed from their system and the number cancelled as I do not wish to conduct business with them ever again :-(