Firstly I was due an upgrade, Carphone warehouse called me 8 times in the space of 2 days to get me to even though I stressed I didn't want a new phone at this precise moment and would upgrade in a month or so when I was less busy. I stated I had an iPhone 5 and was happy, in the end they persuaded me to change my tariff in which my contract would be only a couple pounds less. They sent me a micro sim that is 4G compatible which does not work on the iPhone 5 on O2. I was paying £32 p/m for a phone I already paid off with internet I couldn't even use. To top it off, I went into shop and thought I might as well upgrade to the iPhone 6 and they said I was no longer eligible and now have messed it up on their systems so now I cannot upgrade. They refereed me to call their customer services in which I was told to go back in store to sort it out and now have been messed around for over 2 months. They were great when I first dealt with them but when upgrading again, they have wasted a lot of my time and money.