FNB Fees misleading

I was a client of Nedbank for over 15 years and was wondering why did i even leave nedbank. FNB has charged fees totaling over R4.3k for a debit order of R99 that bounced and R1018 and R273. Their explanation doesnt even make sense because once a transaction is made it goes to being 'reserved' so that when merchant banks the funds are availble. FNB came with stories that didnt make sense. Can some one explain '6 items paid no funds' fee which is also not disclosed in the pricing guidelines when the product is taken. The authority and regulator should investigate this non fair treatment and no proper disclosure of how fees are calculated.