Website glitches are not uncommon, but it could be as simple as having a new address that isn't recognised yet or the format of your postcode etc.
You could try giving CS a call
http://www.o2.co.uk/contactus or pop into any o2 store to buy the phone.
I have no affiliation whatsoever with O2 or any subsidiary companies. Comments posted are entirely of my own opinion. This is not Customer Service so we are unable to help with account specific issues.
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