Exorbitant "unpaid item" charges

Good day

Kindly advise why FNB keeps charging me unpaid item fees unnessesarily. Very recent being a debit order of R130, where I specifically had R150 paid into my account last night to make providion for my Law on Call premium. As soon as the funds cleared into my account, the R130 debit order went off. But this morning the same debit order was returned unpaid and a charge of R105 was debited to my account. Now I have to worry about an unpaid policy, which I went to extremes to make provision for????

I'm currently unemployed and have tried my best not to ovedraw my account but it had been impossible with me paying "unpaid item charges" of over R2000 in the last three months. As it is my loan accounts with FNB are in arrears, this R2000 could have easily reduced some of the arrears but instead of me making plans to pay off the arrears I need to make plans to pay off unecessary bank charges.

Some charges are incured for pending card swipes because FNB debited my account with unpaid charges, and when these charges overdraw the account then all pending transactions are charged R45 or R90. Which does not make sense because the card swipes were made when the account had enough funds for the transactions, so I get charged for FNB honouring card swipes that are pending after they unecessarily overdrew my account.

Please advise me what to do, is it FNB's tendency to put their clients deeper into financial crisis when they no longer have an income? If thats the case then please close all my account coz clearly you are not the best bank for me.