I doubt it. They dont really have the resources, and are not as linked in as paypal is, with the fact that it owns ebay etc. They certainly cant guarantee it, but may have some sort of 'fund holding' while the matter is disputed.
I Think its possible You will need to contact them through customer support to get it done need a valid reason offcourse
Yes, they do, as long as it's within 30 days after the transaction and the scammers still have funds in their account.