Fnb Pending transactions causing bank charges

So i have a gold cheque account with Fnb and what has happend now happend before but i did not still think anything of it. But now this is unacceptable, On the 2 March 2020 i had a amount of R1908, 81 in my account, this was on a sunday i made a purchase of R337 at clicks which left R1571, then i made another purchase at pick n pay of R1070.35 and i requested a cash back of R450. So the actual amount was R1520.35. Then there was a R51 left. I requested a taxify which was R32 which left a R18 on my account and i bought airtime. So my issue is Fnb says or according to their benefits its cheaper to withdraw money from pick n pay, shoprite or checkers. This is a lie, they charged me R100 for the cash back, i was going through my statement, there was a debit order that went off for a amount of R587 for multichoice on the 2nd, and the time it went off i knew there is no money in my account so it will be returned as an unpaid item and the charges are R100 which is fine. I k ew my account will be in a minus. Then i notice that there was 3 unpaid items charged and not just one because i know this is the only debit order that went off. So i called the call centre, i was transfered to 3 different people. The last person was a guy and this was what he told me! When i swiped at clicks for the amount of R337 my account was already in a negative balance, then when i went to pick n pay and swiped again it was still in a negative balance. Then i requested a cash back and the charges for that is R100 and some cents. He also told me that clicks did their banking late, the funds never went off immediatley on my account, i swiped on the 2nd but the money only went off on the 4th, how does that make sense. Fnb misleads people by saying swiping is free and withdrawing from shoprite and these stores is much convenient and saves more on charges but its a lie. Clearly He explained that the R125 for the first item unpaid was for the clicks transaction, the 2nd amount of R100 was forthe cash back i requested at pick n pay nd the 3rd R100 was for the unpaid multichoice item. These charges was all because there was not funds available and my account was in a minus. But the transaction at pick n pay for R1070 went off fine. What i dont get is how could i swipe for a transaction if there was not any funds in my account, how does that make sence. The fact that clicks banked their money late, how is dat my problem, i swiped and the funds was already minused from my account. But now i have to pay bank charges of pending transactions for the bank. This is unacceptable. And it should not be left like this, how much times can the bank get away with cheating us with our money by such charges that is not our fault. Swiping sepose to be convenient but its more a expense now. Its charges adding up, in the end im the one sitting with huge amounts of transactions that was pending and when it clears, the funds are not available anymore. Unacceptable i have never heard such complaints from people banking with other banks.