As others have been mentioning here
https://bitcointalk.org/index.php?topic=118354.120 I also have been double payed (well 180% payed to be precise as nefario is only sending 90% payments at present)
I'm an honest guy and am happy to send the overpayment back. I do however find Nefario's "It would be better to return the coins without me having to chase you for them." extremely hypocritical seeing as he's barely made effort to update anyone as to what's going on and many users have still not received their funds, none of us have received our full balances (double payments aside!), and none of us have received info on our assets yet.
What do people on here think? Should I send the total second payment back, should I only send the extra 80% back, or should I wait for info on my assets first?