Debiting and adding fees when no need to!

I received an sms on my phone on the 17 June 2015 to inform me that I was over drawn. I went to check my account and I am R533.28 in arrears. I have had continuous problems with Nedbank debiting me when they see fit ( eg: 2 weeks later the transaction will run off my account) It is difficult to keep track on what is happening when these transactions are delayed. Nedbank is one of the most expensive banks when it comes to \honouring"fees. I have a debit order that runs off - and I had money in my account"