MTN Is Sh*t

I’m writing this with a heavy heart , I took a phone from MtN 2023 and I was paying them well since that year until this year (2025) January was my last month , then on February they started calling me telling me they have added R900 rands so I’m owing them. They have made my credit score bad 💔I went to my bank and when they check I have been paying them well. MTN has ruined my credit 😭