incorrect charges by FNB

around April or May this year i changed my FNB account Plan from from Platinum to Gold because Gold is for people who are earning a certain amount like me,and Platinum was too expensive, i went to carleton branch to change when i asked for a slip or some proof that i make a follow up with i was told no i will receive an SMS,which i did not receive and after a month the changes were not effected. i then PHONED FNB and the changes were done in two minutes.the following day i went to FNB Carleton center again to change my plan from pay as you use to unlimited and again was not given a receipt or anything again.to my suprise when i checked my account i realised that there changes are not done and FNB has been charging me for each debit on my account and if they are doing that it means i am on PAY AS YOU USE. i refuse to be charged by FNB while it is their fault for not changig the plans while i asked them to.i want FNB TO PAY ME BACK MY MONEY WHEN CALCULATING ITS SOMETING LIKE R200.I WILL NOT PAY MONTHLY CHARGES OF R300 EVERY MONTH NO ITS NOT GOING TO HAPPEN. MY NAME IS MAUREEN