Nedbank Account Closure

I have a business account with Nedbank, for the past 4yrs . However I have not been getting work or money into the business for a while now. The account has always being serviced accordingly, monthly fees paid and no issue at all. Until the account was R59 overdrawn last week and I forgot to make the R60 payment to rectify account. Nedbank, without calling me or sending me communication, decided to close my business account. I don't think this is fair, or just. They could have called me and I would have paid the money. ACC: ********** 836. We need thus account active.