Have you checked the coverage in your area?
http://www.o2.co.uk/coveragechecker
and whether there are any known problems:
http://status.o2.co.uk/
Cleaning or changing the sim might help too.
To support Disasters Emergency Committee: http://www.dec.org.uk/appeals text Nepal to 70000 to send £5
Sky Unlimited Broadband - Windows 10 - Nexus 4 Android 5.1.1
