I've heard that literally hundreds of times. Never once have I heard anyone say that postal inspectors executed a search warrant or made an arrest or got their money back or secured a conviction.
Financial crimes ( which this is ) are way way down on the list of priorities for LEOs and prosecutors.
This is a federal fraud case if a USPS money order was used.
I'm usually on the FAL Files and there have been several posts where postal inspectors where asked to look into frauds paid by USPS money orders, and while some inspectors seem to poo-poo it away, some don't. It seemed that the more the victim pressed the post office, the better the results, just like ANY government agency. So when I hear someone doesn't get satisfaction from the government, my first question is "How far up the chain of command did you go"? I've had to push it with them myself and had I stopped at my first wall, I would have never been satisfied, i.e. paid the insurance money that I paid for.
It's been effective enough on the FAL Files that many people won't take any type of payment except USPS money orders.
Never hurts to have extra charges to pile upon other charges.