I was in a bank the other day.
A man in line behind me was asking a bank supervisor about his check payment to Dominion Energy. The payment was never received and Dominion was charging him a late fee.
The bank employee said maybe the payment was stolen from a Post Office Mail Box. The employee said thieves have robbed postal workers of their mail box keys. The thief then looks for envelopes containing payment checks. The checks are then "washed" and then used by the thief to deplete the victims account.
Suggested measures.
Don't pay by check.
Don't use outside mail drop boxes. Place all mail in a box inside a post office building.
Did the bank employee confirm that the check was cashed? It seems he must have but it's not clear that he did.
I'll also add that the post office is far from making sure mail gets delivered in a timely fashion.