I want my R300 back

I’m tired of FNBs pathetic service. I checked my Cheque account and found R300 was debited on the 21/10/2020 with reference:Items paid no funds. I called the call centre and spoke to Leganisang Mashigo who advised me I was charged a dishonor fee since I didn’t have enough money when they debited. I deposited money to my account and no debit order came back unpaid.I don’t understand why I was charged R300 how pathetic is that. I want my R300 back & it must be reversed. I have been baking with FNB for almost 20 years since I was in school but I’m starting to loose trust in them. I have been having problems with FNB 2 months ago it was their Homeloans division who failed to assist me