iPhone 3G no service problem -Help?

[natdeamer]

Hi,
Having some problems with my iPhone 3G.

It is unlocked with yellowsn0w and was working perfectly fine with my T-Mobile UK sim card.

Today, i started getting "Error could not send" on SMS
and phone calls were just beeping twice then hanging up (unconnectable?)
Checked Sim card in another phone - All ok.

So i did a restore in itunes, and put my O2 simcard in. Now i am just getting "No Service"

I jailbroke and unlocked iPhone again, put my t-mobile sim back in... same problem. Full signal, unable to send sms or make calls.

Both O2 and T-Mobile sim cards are working in my N95.
T-mobile: Signal but unable to do anything
O2: Just says No Service.

Help please? =]

[dejawoo]

Don't know your phones info.But
*Be sure baseband is 02.28.00
*'' '' without simcard pin lock
*Try flight mode on/off
*Also,after you install yellowsn0w via Cydia,you should return to the Cydia main menu then reboot your iPhone with the 3rd party sim installed.Wait for the slide to unlock screen,then wait 10 or 15 secs more.If you don’t see your carrier name pop up,then remove your sim, reinsert it and wait 10 secs more.

[natdeamer]

Tried it all.
Phone was working perfectly fine for 2-3 weeks, then just stopped.

[Dipesh]

same has happened to me as well. cant figure out why as i have two iphone 3g's one on O2 UK and the other on Vodafone UK and both have no service all of a sudden

[natdeamer]

Did it happen yesterday morning?
I brought my iPhone Second Hand (But still sealed).
Now im scared that the IMEI has been blocked.
O2 told me yesterday it was fine then i wanted to check today and O2 wont tell me.
CheckMend online say that the phone hasnt been blocked on any network around the world.
I think i might just have to take it to Apple.

[Dipesh]

yep it happened to me yesterday morning and unable to use it since

[natdeamer]

I got my IMEI checked today via.
CheckMEND - The Global Second-Hand Stolen Goods Database for Public & Trade Checking - its been blocked by UK networks.

EITHER the B*STARD i brought it from has reported it as lost or stolen or something! And suprise suprise i cant get through to him.

OR O2 has discovered i was using the iPhone with a t-mobile sim? (Unlikely)

Did you buy it second hand (i got mine from GumTree) or from a shop?

[v3r5u5]

It seems that this problem is happening while you travel. In my case the No service appeared while I was going from Canterbury to Coventry. In Coventry I changed my sim(USIM) which fixed everything. But on my way back to Canterbury I had the same problem again, No Service.

If this happens while travelling, it is most possibly to be a software problem, since the sim was working before. So, I left my iPhone 3G dry out of battery (Not even the red battery was appearing when I was pushing the buttons). Then I charged it without the sim and after that I reinserted the sim back in.

Everything started working again!

Hope I helped.