You could split the difference. Send in the paperwork but don't tell them you did it, and don't send them a copy. Odds are they don't check the USATF site.
I'd bet they will pay you anyway, especially if they think they may want to work with you again.
I once did a half-marathon course for a friend. Sponsorship evaporated before I was paid, and I was reluctant to dun my friend for the fee. So I ate it without relish.
I've done hundreds of courses and this was the only time I got stiffed.