Hi and Welcome,
Didn't you check out coverage before signing up to a contract to ensure you would receive good Network Signal and data coverage where you reside, commute and work.
http://status.o2.co.uk/
I tried out all the main Networks before choosing 02.
Regarding texts have you tried tho method of giving your sim card a wipe down, and or have your sim card swapped for a replacement.
http://swapmysim.o2.co.uk/
Put your sim in an alternative handset to see if signal and services change to rule it out.
