Yes, might have joined the club
Selling on fb marketplace. Buyer has overpaid a small amount via PayPal goods and services. I clicked refund in the PayPal transaction. They then sent the correct payment. Is there anything further they can do? Their address is also an "educational institute" and I vaguely remember these being hard to track after being shipped to. Package is nearby and debating whether to cancel and retrieve it. There is seller protection plus tracking that I've added.
Sounds like a scam to me