ABSA over charges their customers , especially for internet banking

Dear ABSA for the past few months I have been over charged for bank charges. This month I have been charged over 500. I have raised this issue with ABSA but the consultant who was assisting me , could not see why I'm I being over charged. We calculated all the fees on the bank statement and still it didn't add up to the amount that was charged. I really fail to understand why am I being charged so much money. This really inconveniences me and my family. May kindly attend to this matter.