My service isn't very expensive (one of the lower ones in the industry).

The origins of these people are often problematic countries (places I couldn't accept a payment from even if I wanted to).

Some of these individuals (~30%?) seem to be coming from legit domains and verify their email but don't appear to be the target audience. They often try to pay without using the service. I believe these people have compromised mail servers and are trying to test stolen credit cards.

I'm not greedy.