I have two phones atm. My new Nokia 5800 which has developed a problem and won't let me text at all (and it's on contract) and my older Samsung G600 which still works fine (and is on Pay & Go). They're both on o2, which tbh is a great network until you get a problem then they'll just repeat over and over the solutions from the website even when you're practically screaming at them that none of them worked.