I got sent 2 iPhones would you sell one or give it back?

O2 sent me 2 brand new iPhone 5's. I'm keeping one, to be honest I would much rather sell the other for £600 than give it back. How likely do you think they are to claim it back and what would you do? Also if I did sell it and they claim it back if worse comes to worse I could always buy another one and send it back not making any loss?

Had them since September 18th

All opinions welcome and much appreciated

Thank you

btw I did order one haha

Added (1). It was a free upgrade as part of an o2 lease tariff where you give back your old iPhone. I have checked invoices and they state only one iPhone was sent out.

Its pretty hard to say because they don't usually send out an extra by mistake. They might have though you ordered 2.So I think you should check your bills and all that just in case if they charged the wrong amount.

Keep both or sell one and get a blackberry. Its much cheaper. Would come in handy when you can't get your hands on a iTunes card

They will catch up with you eventually when they do a quarterly audit, then they'll demand the phone back or its full value, oh and if they're feeling vindictive they can put a cifas fraud warning on your credit history and then you're stuffed for 12 years, double the length of time adverse history normally stays there.

Don't be surprised if they realize it and expect it back, I would make sure you aren't being charged now or near future.