The phone number of your dongle sim is all that's required on the blue O2 landing page.
Have you tried any other wi-fi sites, or connecting to a wi-fi router to check the wireless on your phone/pc/device is working ok?
To support Disasters Emergency Committee: http://www.dec.org.uk/appeals text Nepal to 70000 to send £5
Sky Unlimited Broadband - Windows 10 - Nexus 4 Android 5.1.1