[PROBLEM] Suddenly no signal & no working connections

[sinoo]

Hi,

I have a problem with my Diamond.

I use my phone nearly without switching it off. About every 5 days my device loses his signal and stops every connection. Unfortunately not with showing me.

It still shows signal strength and connected status of HSDPA, but there is no connection anymore. If I'm called they are connected directly to my mailbox. I no longer recieve SMS and I'm no longer online. I can only notice this problem, because I cannot send an email or sms, cannot make a call or surf the web.

Strangely the fault is gone, when switching flight mode on, then switching phone back on (with PIN).

Anybody an idea on how to fix this. Did this happen for someone.
May I try a radio upgrade?

Please answer asap.