[codazoda]

Can you verify, even after the purchase, and automatically refund them?

As an example, will the spammers click a validation link?

[ElbertF]

I send a verification link to new email addresses before accepting payments. They do click them.

[fencepost]

Do those verification clicks come from the same ip address as the initial order?

[ElbertF]

Good question, I don't know. I could fail the verification if it doesn't match.

[fencepost]

It's not 100% because you may get some folks who sign up on a PC but deal with email on a phone, but if they're on home wifi then it'll be the same address. If your emails are sent immediately then differing IPs seem like they'd be rare.