ok, i have had simila but with an Orange contract on a phone.

You need to get down asap and cancel, it wont be no longer than 14 days max as a cooling of period athough these guys say 7 days

http://www.orangeproblems.co.uk/mobi...opic.php?p=403

and these say worse

http://www.moneysupermarket.com/comm...eas-14478.aspx

I got stuck with my Orange contract exactly the same way, they said that the signal was excellent in my area,but there was none at all, the best signal i got was 1 bar only if i stood in an upstairs bedroom.
When i complained they told me a mast was down in my area and it should be fine when fixed,they told me a load of exuses over the 12 month that followed, only when i got very very arsy with them would they agree to cancell my 18mth contract 6 mth early.

The point is i believed them and got stuck in a contract where i couldnt use the phone in my own house,the false pretenses thing will not work with Orange because believe you me i tried my absolute hardest to my contract cancelled, even told them i was going to see a solicitor as they were not keeping thier side of the contract by me paying them for a service that i couldnt use becaus ethey were giving me no signal.