I had some sim cards come through for O2, on the packaging it was all about O2 Unlimited, the reason i got the sim cards.
I noticed soon as i registerd i was on PAY & GO - TALKALOT, didnt want to top up phone if i was on that tariff so tried to switch plan to O2 Unlimited and had to wait 48 hours before it would change.
24 hours later told i couldnt switch to that tariff by text msg.
This mean your forced to spend on a month on PAY & GO - TALKALOT before you can go to Unlimited?