Disclaimer: I own a used iPhone 5 and never bought one brand new. Many carriers like T-Mobile began a blacklisting service a couple years ago to prevent stolen phones from being sold. Little did they know, they opened up an entirely new opportunity for a new type of theft simply because of their policies. IMEI Verification Won't Help You probably received some advice to check the IMEI number to make sure the phone was not blacklisted either due to theft or no payments. You go ahead and call your service provider or use their online tool and they verify the IMEI is good. A few months later the original buyer reports the phone as stolen to defraud insurance (that's a crime by the way). What you may not realize is some companies such as T-Mobile has no safeguard against this. "T-Mobile IMEI look up tool is for informational purposes only. The status of a device is subject to change at any time. T-Mobile is not responsible for any device blocking that is not disclosed or that occurs at a later date." Do CDMA networks protect me? Apparently these tactics makes the IMEI useless for GSM carriers. CDMA carriers, however, such as Verizon and Sprint restrict who can call and blacklist the phone. GSM carriers as far as we know do not do this at all. If you buy a Verizon phone which are always unlocked, Verizon may be only be able to do this if you are their customer. Obviously, people bring them to other carriers so that may require more work. Then can T-Mobile protect me? I spoke with a T-Mobile rep that claimed you can verify your ownership of the phone, in case it is blacklisted, by providing the Ebay receipt. YMMV of course, since some cases of showing evidence of the sale didn't help. That still doesn't solve the situation of preventing the problem - it's only a workaround if it does come up. They also said in order to verify if it's not financed, you must show a copy of the receipt that shows it was paid off. But then, if it really was paid off then you shouldn't even have that issue anyway, right? Can a factory unlocked phone be blacklisted? Yes. Even though someone would likely not be insured or have any incentive to do this, technically it could. Ebay/Paypal Protection If your phone gets blacklisted months after a purchase online, you are way past the protection window for Ebay and Paypal. T-Mobile and AT&T only answer to the original buyer, so no help there either. Other FAQs: Sealed Phones Require The Same Checks This guy got a new contract, bought insurance, didn't use the phone, then sold it to someone and the blacklisted it. In other cases, some people even have a plastic wrap machine to reseal phones. I bet this is rare though. In either case, you should check sealed phones with the same scrutiny as used phones. Other FAQs: Identifying a Legitimate Seller It's not as straight forward as you think. Many phones bought from highly reputable sellers on Ebay still somehow get blacklisted months down. This is because resellers try their best to buy legitimate phones, but they are no more protected than you are. Other People's Experiences Macrumors 2013 What To Do The current advice is to stick with Verizon/Sprint. They will verify the financial situation of the phone and may be able to remove the original user from the account. Any other advice is welcome!