Iphone 4S Switching EDGE to 3G error

Hello

I still have this problem connecting to my iphone 4S :

https://discussions.apple.com/thread/3794530

the resolution of the problem in apple does not advance.
After eliminating the cause of a different carrier following tests:
http://www.youtube.com/watch?v=1wQjKU8NRUQ

http://www.youtube.com/watch?v=nroJz8nkHmo

The problem comes from Apple and no one has a solution.
Here since last February perciste problem that I am in my 5th exchange and nothing has changed.
Has anyone there a similar problem on his iphone?
thank you in advance for your info recovered.