Hi, Recently bought a samsung galaxy s2 (second hand (unlocked)) and was happily using it untill friday when i suddenly stopped recieving texts, and when i try to make a call it just says not registered on network, yet the mobile internet is working fine, any more info needed just ask, thanks.
Mobile network not found:
Check to see if there are any outages in the mobile network where you are by entering your postcode here http://community.giffgaff.com/t5/Service-Updates-Notice-board/Find-out-the-service-status-of-your-ar...
If OK then see if doing a manual roam helps http://community.giffgaff.com/t5/Learn-giffgaff-Top-Tips/manual-roam/m-p/3345471#M32502
Also try turning airplane mode on and then back off.
If no luck then try rebooting your phone.