Nope I don't think you can put it in upside down, I have tried it also in my iPhone 4 with the nano sim adaptor and it also doesn't work just says no service. I went here to see if I could activate it or something:
t-mobile.co.uk/newsim
But it said my number was incorrect...
Have you recently used a PAC Code to transfer your number? You will get no service for up to a few hours while they process that. Try Turning your phone off and on again.