Ewallet reversal

I've switched over from nedbank to fnb about 4 months ago. I'm happy with the service they provide and with their bank charges. Although there's a couple of things that I think they can improve on. Like when u on the secure chat they switch u from one agent to another without warning and for no reason at all and also once they reply they take forever to keep the conversation going. That's very frustrating. The other thing is reversal of ewallet transactions. I lost a lot of money through that. I'll tell u what happened. I advertised something on the net to sell. The buyer came to me looked at the product and payed me via ewallet. Little did I know that he can immediately reverse that transaction by only paying R16 . I only found that out when I want to the ATM to withdraw the money only to find out there was no money. I contacted fnb n they told me about this immediately reversal. I think fnb should really be more stricter in that matter. Otherwise the ****** out there is going to take big advantage of this. And that cost me alot of money.