Poor system

I had funds in my account that I left for a debit order but the boom I’m charged R105 for items unpaid no funds 01 how come when the was money and why would you guys charge me that money R105 that’s so much even if it failed the debit order, I want my money back I have been watching my account some money been going out nje !!! I’m moving my account somewhere shame I can’t this is ****