I had IOS7 Beta and someone I know put it on my phone back in July and now I can't update since I'm not a developer. What do I do?

Help ! there's a screen that says: "This Device is not registered as a part of the iphone Developer Program. If you are a member of the Iphone Developer Program Please register your device." I don't want to have to pay the fee. Any other way? I tried the recovery method already and it didn't work.