Standard Bank

Good day. I had an overdraft on my cheque account at Standard Bank. I switch banks and my account was overdrawn. I had some financial issues and this account was handed over to Daly. I arranged to made payment of R200 and have been paying this every single month and my balance decreases over the past two years. As of February 2020 when my account was on R600 and something they charged me an extra R107 for service fee that was never charged during the last years I have paid and al of a sudden I see absolutely no difference in my balance. Up to June I have paid R1000 on a balance that was R600 and something in February. I sent emails to Daly and spoke to consultants and no one can give me a satisfactory answer. How can you not charge a service fee for more than 2 years and all of a sudden when the account is almost paid up do this? Im am very disappointed and need urgent advice before I made any further payment.