Hi guys, I'm about to buy an iPhone from a seller on eBay. He describes it as a working DEVICE except for the telephone part. Basically it says the handset its locked and cannot be used as a phone, giving the "No Service" error in the left corner, he also said he believes (he didn't tested it) that it works with foreign SIM cards. Now, I'm asking you, what can be the cause of this? Worst and best case? Should I even buy this phone? Many thanks to all!