Unhappy service and Client

I was charged an honouring fees for transaction, when I had money in my account for it. I feel that Nedbank has charged me unnecessarily for transaction that went through successfully on my account, since there was money in my account as this is a huge concern for me about my account with nedbank funds are being debuted but i don't know for what and when i go to a branch they just advice that it service fees but service fees that adds up for more than R400 i just think this is ridiculous.