Edgars is a ****.

I have an Edgars store account, which had a balance of R1780 as per my February statement due 1st of March. On the 23rd of February I made payment of R1781 meaning I settled my account in full. However to my surprise this month of March I get a Statement from Edgars saying I owe them. I called to enquire about the amount owed. Interest charged and service fee on an account which was fully paid. I was told by lady called Zandile that am charged because I didn't request for a settlement amount, my question was, what interest am I liable for because this account is paid in full actually Edgars owes me because I over paid? Still didn't understand her response regarding my question. Maybe am stupid or something don't you accrue interest on an account that is owing or overdue... People please stay away from Edgars