Poor systems and service

Yesterday I made a deposit into my nedbank account in one of the ATMs, instantly i got an sms showing the deposit and my mobile portal updated accordingly.. Later on I was able to send money from my Nedbank to my FNB and the transaction went through, and my account had a positive balance. Then this morning i wake up with a notification that my account is overdrawn, upon calling the consultants they told me a deposit takes 48hours to reflect. In this present day and age how can a bank be that backward, now I Keep getting messages to make a deposit in order to avoid my account being on negative but clearly i shouldnt be having that problem.

I called, emailed my banker because all the other bankers can not assist me but guess what since morning now its afternoon, i have not heard from my banker, im beginning to wonder if i really need to keep my business with Nedbank or just move to the next bank,