POOR SERVICE!!!!

We have a Miladys account and the account was almost recently paid in full with a balance of R75 left. This balance was from last month July, recently I logged in to see what the new balance was and I saw it jumped to R111.00 outstanding. How does Miladys charge SO MUCH INTEREST when the account was not used at all. I sent numerous emails to Miladys and no one had the decency to respond. I should have closen the account at the time when the amount was paid in. Totally unprofessional service from this place!!!!