They don't need that info, if its within 180 days of payment tell them to click on the transaction in their paypal account and using the refund option bottom of that details page issue a part or full refund.
If they don't want to do it that way then tell them to use the friends/family option so that you don't pay fees and they can pay to your paypal email address or mobile number via the app.
Advice is voluntary. Kudos / Solution appreciated.
