I have mine and my mum's contract with them, after a few months, my phone started cutting off calls every few minutes as did my mums, they told me both phones must be faulty, so we both now have brand new phones and still the same - so very expensive 'advice' from o2. I have phoned/e-mailed/live chat with them and they have more or less just said 'oh well the coverage says ok in your town' - not offered any sort of solution, it can be seen on my bill that phone calls constantly cut off. Friends of mine are having the same issue so it is definitely o2s issue. As long as they have your money they don't care!!!!