I would strongly recommend never using PayPal F&F unless the person actually is your friend or family.
If they insist, just step away.
I had it happen in an FB group just this week; someone had something in the UK which I wanted and would have otherwise cost me double from the US after shipping & fees.
The seller would not budge on F&F, even when I said I'd cover the fees for G&S, so I didn't go through with it.
Just don't pay for goods using F&F.