Good Morning,
Try removing your Sim Card and wiping it down to remove static build up.
If you have a spare phone it's an idea to try your sim in that one, if it accepts the same sized sim, to rule out any issues with your primary handset.
Also their may be an issue with your local mast (s)
Check here to see http://status.o2.co.uk/
Call 02 Customer Services to ensure your account is ok.
Contract Customers.
From your O2 mobile 202 Free
From a landline 0844 809 0202 5p / min
From abroad +44 844 809 0200 Free
PAYG Customers.
From your O2 mobile 4445 25p per call
From a landline 0844 809 0222 5p / min
From abroad +44 7860 980 202 International rates
Monday-Friday 08:00 - 21:00
Saturday 09:00 - 18:00
Sunday 09:00 - 18:00
Live Chat Services are fine for Low Level General Enquiries, not connected to Account Enquiries.
Also look in your phone for a setting that Resets your network settings.
Soft Resets by turning your phone off and and on wih removing the battery if possible can help.
Other options are to carry out a hard reset - Google for instructions on how to do this for your make of phone.
Hope all your services return asap.
Take care.
