I have a barred in the uk iphone, which country can I sell it in?

Don't just say oh you stole a phone blah blah blah, I paid for it but I wasn't old enough when I signed the contract so o2 barred the phone and won't give me any of the £150 I paid for it at the start of the contract. So yeah barred in the uk, will it work anywhere in the world or outside Europe or what? I heard some countries share the 'black list' (man this makes me sound like a criminal) so yeah any idea where it will work where not?

Iran

100% won't work in Europe, USA or Canada. And there's a very good chance it won't work any where Telefónica(O2's parent company) has a mobile network.

Some people may say to change the imei number which is illegal and I don't recommend.