FNB to FNB funds not reflecting. Making my business look dishonest

A client just did a deposit from FNB account tou FNB business account and the funds are not reflecting and the client is now furious as I told them the funds are not in my account as yet. This is a damn business account and how the hell do I run my business when I can't use the funds paid into my account making my business look *********** and dishonest. And I swear I will take legal action against FNB if my client opens a case of ***** against my business as it looks as if I'm trying to steel clients funds. By saying I haven't received their payment. Please don't make me look like a ***** and sort this **** out immediately. I will be moving all my accounts to another bank