Issue with iPhone 4 and Swisscom provider: Loosing 3G/Edge and not getting it back

Hello,

We have several users in the company using iPhone 4 with Swisscom Carrier in Switzerland. I have various issues with them, I will focus only on the major issue we have with 1 user, any help would be greatly appreciated.

The user uses his phone at work to receive professional e-mails and updates in his calendar. When he goes back home, there are some areas on the way which do note receive any data signal. At home, he has no data signal and uses wireless network. When he goes back to work the next morning, sometimes, the iPhone does not pick the data network at all (whether it's 3G, Edge or GPRS), however he can receive and place phone calls. Turning on then off the airplane mode does not help. Only a reboot or reset of network settings temporarily help.

We have already:

- Changed the iPhone (a few months ago)

- Changed the SIM card (a few months ago)

- Reset the network settings (last week)

- Updated to latest iOS (last week, to 4.3.3, was 4.3.2 before)

- Called Swisscom who says it is an iPhone issue

Following the network setting reset and iOS update of last week, I went to the -1 floor, where there is no network (data and voice), went back upstairs and the phone would pick up the data network just fine and quickly. I did it a few times with no issue.

We have not much option left, we will change the phone again, so that the user is aware we are doing something about it, however I fear the issue will show up again.

Any clue in the Apple guru community? I'm at my limit here 😐

Thank you very much in advance!

Flo.