Charging of ridiculous fees

I've been charged ridiculous fees on my Cheque account. Last month I was charged fees of R770.00 for transactions that the merchant processed late when I didn't have money in my account and I was charged R110.00 for each transaction regardless of the amount as some amounts were R53 and less. I queried the amounts and were reversed but 5 days later I was again charged an amount of R440.00 same transactions. My card is not a Credit card I cannot transact if I don't have funds available, how does FNB say I used the card while it didn't have money? It's a Cheque account, you need to have money to use it.As I write this, my account on MINUS with R955.00 of charges, how crazy is that. I was forcefully offered this Premier card with it's ridiculous charges and when I ask for a downgrade back to the Gold cheque account, nobody's responding but I get sms's daily that my account's in excess and I need to deposit funds. I need those charges reversed please!!!!!!!