Repeated Wrongful service fees on account

I don't remember their service being this bad. I opened a new cheque account in March last year. Since then I have had charges go off on the account for payments that were supposedly made when I had no funds in my account. This will range from R115 to R180. On one occasion I was able to claim a refund because I had proof, unfortunately it is no longer the case this time around. I purchased something on 02 March 2022, the funds were reserved, yet on 28 March I was charged again for the purchase. According to fnb the merchant banked late and the reserved funds were returned to my account, I am certain this is not the case. However, as usual I cannot prove this because I contact messages have been convienently deleted. Fast forward to two weeks later after having been told on two esperate occasions during this period that wrongful charge for unpaid items would be reversed to my account, I Co tacted them again to find out why this had not been done and I was told that I needed to provide proof of the message sent by the bank assurinf customers that they would be refunded. Of course they have removed my in contact history so this will not be possible. This is how they operate, since the first day I opened this account in 2021, I was just too occupied to take action before. This will definitely be the last time as I can see that this is how they take clients for a ride.