I agree with PPs - I used to work in the Finance department of my company. Yes, occasionally we had situations where customers wrote cheques on a since-closed bank account, or had confused us with a similarly-named company. These were fairly easy to resolve.
However, there was never any way to "prove" that we never received a missing cheque, and lots of customers just didn't seem to understand this. At that stage is was truly out of our hands, and many just didn't seem to get the concept of "you need to check with your bank about this".