iPhone SE won't connect to iCloud/iTunes/Internet

Hi,

I picked up my new iPhone SE today, but I'm having trouble getting it working. I upgraded from an iPhone 5S, so backed up my old phone and then set up the new iPhone SE from this backup.

Everything seemed to be going ok until I was asked to enter my iCloud password. Every time I try to enter the password I get an error message or it just times out. Also, I cannot connect to the internet using Safari.

I have tried connecting using 3G, 4G and Wi-fi but none work.

Because the phone is tied to my iCloud account, and has Find iPhone turned on, I can't restore it to my backup using iTunes. I can't turn off Find iPhone as due to the lack of internet connection it won't accept my password. I also can't do a full reset from the phone settings as again it asks for my password but can't seem to connect!

Anyone any ideas what my next step could be? This is the first time I've had any trouble with an iPhone, but I'm all out of ideas!

Thanks,

John