Nedbank is horrible

Nedbank is the worst bank. I was buying groceries for my family today (26/08/2018), whilst I was paying it said I have insufficient funds, after checking my mini statement it showed that I have account balance of R684.50 and available funds R184.50. I just want my money and to close this account I am done with NEDBANK, it is just chowing our money. Please assist me in getting back my money, it's my children' s money, I am stressed by this matter. Please help me.

My nedbank account no.: ********** 480 Account Holder: Nomvula Thela Contact Number: **********