Ackermans/Tenacity

I was handed over with my Ackermans account due to retrenchment and couldn't pay anything for almost a year because I was unemployed for a while. This matter were added to their system . They knew about it . In 2020 I paid my account in full . Also have my paid up letter . Till today there is still a amount of R755 outstanding wich I can't understand my account is fully paid. I also wanted to re apply and they told me I will never ever in my life be able to have a account with Ackermans because of my previous situation. But in the end my account is paid up , and it was out of my control when I got retrenched. It's not like I wasn't paying anything I arranged a full payment and I did.