MTN refusing to help

In May 2021, someone claiming to be from MTN phoned me. This person had all my personal details like ID number etc. She claimed that someone was busy with a sim swop in Gauteng with my cell number and I need to give her OTP which I will receive so that we can prevent this. So the process started and I gave her OTP, 3 times. When the call ended I looked at my MTN app and saw that someone tried to buy 300 gigs of data but it seems they were unsuccessful as it was on my account now. I went to the local MTN store and explained that it wasn't me buying this data. They said they couldn't help me, because it seemed as if I bought the data. I went to the police for an affidavit, went back to the store and they filed a complaint. Now after 3 months nothing is resolved. All I want is for MTN to take the 300 gigs off my account as they want me to pay for it now. I don't have the money. My service was suspended, I can't make any calls and the next step is now blocking my service. I have been a client with MTN for 25 years and they don't want to help me. If they go back into my history with them, they will see I have never used so much data. All I want from them is to reverse the whole thing. This is how they treat their long-time clients. Terrible service.