@smoke: i had exactly the same problem the other day, it shows 3G but no data.
changed to EDGE still the same no IP address from QTEL.
I tried so many diff things, Reset all network settings Everything. Did a search and found that other people have same problem since 4.3 update. They gave some workarounds but alas that did not work.
Then I just gave up, towards the end of the day around 15:00 it just started working again, without me doing anything. I suspect its a QTel issue, but as usual they are no help.
Mines working fine again.