Why should I pay for something I did not agree to???? And then not get paid back???

Have had a Milady's store card for a number of years. Love there clothes. A few month ago I paid off my account, as I just had not been able to get to the stores due to being ill and immobile. I have paid my account diligently since I have had it and with the last payment I made I actually overpaid my account balance in that they owed me money. I have had the same card since I opened the account and know they charged me a fee if there was a balance due, or insurance on that balance, which is not a problem. HOWEVER.... after having overpaid my account I realised that I am being charged R45.45 Service fee as well, with or without having balance. So although they owe me money, they just keep on reducing the balance I overpaid by the monthly “costs”. I had not notice this before, as I frequently pay on the overall balance I knew I used the account frequently. I called them today. They (Milady’s store card div) have been taken over by RSC and that this charge is due to my clothing account I signed up for now being classified as a credit card. Well it was COVID, I have been ill for the last 13 years, but more so that the last 3 years, my husband passed away, and kids immigrated… I can not recall that I EVER AGREED to this. They confirmed per my telephonic conversation that we can’t give you your money back but you can close the account so that it would not cost you anything. I did not sign up for an account that would cost me anything if unused!!!!!!!!!!!! This amount to A LOT OF MONEY for someone on pension now which is needed for other life essentials. I agreed to a credit limit, an insurance fee on an outstanding balance and being charged interest at a prevailing rate, NOT THIS!!!!!!!!! This is plain theft of money of a pensioner, or anyone and strong arming me into “just close your account” tactics…. So forcing me to then re-apply if I ever need it again and then obviously have the new terms. The arrogances with which these companies conduct themselves are astonishing. I should not be paying for something I did not agree to. I will post the same complaint on RSC as well as Milady’s. Its should not be my cost, if I did not agree to it or a company decides to pay someone new to manage their cards??? Right????