my phone wont activate

I have had an I phone 3 gs for over 4 yrs now and never used I tunes. My daughter convinced me to install some apps that would help me and I created an account with I tunes which was accepted. Once I plugged my phone in to I tunes, it asked me a series of questions and insisted I upgrade my phone to the latest software ios 7 I think or maybe ios 6. I followed the instructions, now my phone has been wiped clean and the message I am getting is that it cant be activated. My I tunes isn't recognising my phone anymore and I cant rely on my back up which I did before updating it.

I am now stuck with a phone that has nothing on it and I cant activate it. What can I do as I don't have the original box anymore. It was unlocked correctly by my last service provider 3 yrs ago with a proper PUK code, but all that data is long gone now.