iOS 5.1 severe problems to connect to a mobile phone network
My iPhone stopped working as a phone.
Can't make/send or receive calls and text messages after updating to iOS 5.1.
It's like the phone function of the iPhone has been disabled.
When I check my settings it appears that it is connected to my local service provider. In the top left hand corner of the screen I only get one connectivitiy bar.
No matter where I am.
What can I do? How can I fix this or do I have to wait untill the guys at Apple Inc. come up with iOS 5.2?
iPhone 4, iOS 5.0.1