So far:
Received 2 payments (totalling £720) this evening for goods sold (not on eBay) for £360.

Buyer contacts me saying her computer crashed whilst finalising the first payment, and she made the payment twice in error. My Paypal account has both of these payments listed.

The seller has requested that I send one of the payments back, which I guess is fair enough, but I'm worried that if I send £360 back, and then both payments are subject to some sort of chargeback, then I'll be out of pocket.

Should I issue one payment back as a refund, or could this be a scam?

First question is have you sent the item(s) yet?

Same thing happened to me.

Contact Paypal first and inform them what has happened.

If you send the payment back as a GIFT there will not be any charge.

Nothing sent yet Pinin.

I'm thinking issue one payment as a refund (which I assume there's no comeback to me on) and keep the other?

Yes refunding the payment incurs no fees etc.

And no risk either?

What would be at risk?

There is a option to refund full or partial payment. There is info on paypal about what to do.

Thanks - just being hyper careful, heard some horror stories recently!

Just don't send it back as a gift; make sure it's a refund, and make sure you alert paypal that you have received two payments, one of which you're refunding.

why not send both of the payments back and get them to redo the one proper payment?

Send 2nd repeat payment as a refund and nothing else - not as a gift (as although appears innocent, that could possibly be the scam for the reason that if the sale is then contested you could loose that and not recover the gift). Contact paypal if unsure.

Yes, you could loose that.

Have refunded the 2nd erroneous payment, and kept the first.

Also contacted PP and explained what happened.

Fingers crossed all sorted now - did smell a bit fishy to me, but noticed today that both payments made via 'mobile' so quite easy to do this twice I guess.