I'm looking to buy a smartphone on eBay - probably a Samsung Galaxy S2 or HTC Desire HD. Obviously any eBay gadget purchase has enormous caveat emptor anyway, but I'm trying to work out how safe it is to buy someone's "unwanted upgrade". I'm assuming that, when a mobile company sends out an upgrade, the mobile company will continue to own that handset for the duration of the contract its on - ie the phone cost is effectively being paid by the contract holder on an HPI basis. Thus if someone sells an "upgrade" - or phone on any sort of contract plan - then the buyer is at risk of the phone being blocked by the original mobile provider if the related contract is cancelled or reneged on (ie same as a car or other goods with HPI outstanding)? Does this happen in practice? Is there a safe way to purchase such a handset - i.e. contacting the original provider with the EMEI number and checking the contract status? Is there a way to clear any contract link, or is it a case of returning the handset to the vendor as a bad sale? ???