nedbank honouring fees

I am so upset with Nedbank and I am planning on closing my account for good. Nowhere have I signed any agreement stating that Nedbank should honour any transaction and charge this fee. I'm mad because I check my balance before I spend money. Why were those transactions approved at retail stores and only to found out from you guys that my account was overdrawn. I want that honoring fee reversed and I want to know what is the most reliable balance!!! I am closing this stupid account.....mxm