iOS 6 in my opinion one of the best ios for FaceTime and iMessages because it's so well integrated. And downgrading does not solve all issues. If this was a case of a 4s instead of a 4, then the op would be screwed since the 4s is not downgradable.
It was working before I jailbroke it then after I jailbroke it iMessage and FaceTime stopped working so I restored it and updated it to 6.0.1 and turned on iMessage and FaceTime in settings but they still won't work.