Had my iPhone 3G for ages, and now NO SERVICE for months!

Hey there,
About three months ago my iPhone 3G started to show NO SERVICE in the top left corner. I've tried everything,
*Different sim cards from 02 (the original iPhone carrier in the UK)
*Network refresh
*Restart/Restore/Complete wipe etc

I know the internal antenna still works, as when I go into settings, and carriers, it finds all the carriers available in my area.

However, I can't recall exactly but I think NO SERVICE started showing shortly after I upgraded to iOS4, but friends with 3G's have upgraded no problem.

I'm really stuck with this one, as a student with no job, this is a big money loss for me. Help?!

Hannah

well Thank you Mac Forums. Again you have responded extremely well.

And you have of course contacted Apple about this and/or taken it to an Apple store so that the true experts with the device can see if they can figure it out for you..or were you just hoping smart-aleck responses here were gonna give you an answer??

Regards

Why not just try downgrading?