Well, after many years and a great many commissions bought, I've finally been scammed.
This person took my money many months ago. After failing to respond to any of my notes to check up on how my commission was progressing, he started a new journal advertising commissions. When I responded to it, he quickly deleted it. He pretended to not know what I was talking about when I reminded him, and made some inference about being hacked. I forwarded him our exchange via Notes. I haven't heard a peep since. I have seen no artwork nor a return of my money.
I suppose I should have known better when he requested payment by means of an Amazon gift card. Let that be a lesson to everyone - Paypal has safeguards.
I'm actually beginning to doubt that the art in his gallery is even his. Not that it matters at this point.
At least I learn from my mistakes. Never again.