Just because you have received your customer’s check, it does not mean your troubles are over. The title of this blog says it all: Don’t start celebrating until the check clears!
In case you don’t know, there is a period of time after you deposit a check in which the bank makes certain that the funds are actually available to be deducted from your customer’s account.
Back in the Stone Age when I was starting out, this used to take 7-10 days. If there are not sufficient funds (NSF) in your customer’s account, the check will not “clear” and will be returned to you. The amount of this check that you thought was deposited into your account will not be there.