Bad bank service

Disappointed and tired is an understatement. The frustration this bank keeps causing. I'm penalized a R300 and R200 for transaction that they claim I didn't have money for. 27th March on a Saturday I got paid, took my family out on a lunch at Spur,swiped my card and we were good. Fnb decides or claims I have made the purchase on that particular restaurant on the 1st of April and for that I'm penalized because there no funds on my account. Really? Another transaction that happened in February already that was apparently never processed as well even though I got all notifications that it went through, this transaction was only adjusted in mid April and I have to be once again charged fees for their delays. I don't want to mention how expensive their fees are, what would cost you a R10 fee on a normal bank, at fnb will be R300. By the time you get paid your bank balance is sitting on minus 2k A day light *******. I have called and exhausted airtime to only get different answers to my query. I'm so confused as to do they even know what they are doing. Where do they think we get this money they ******* every single month? I can't even downgrade to a normal card because I can't even finish paying overdraft because I owe them a minus every month. This is emotionally draining and taking a person 10 steps backwards. I want out but unfortunately I'm tied up with long term commitments made with them. Banked with them for years yet I got my car with a different bank. They hate us.