i think you will find the pay as you go top up cards are activated when they are sold at the point of sale. I bought one for orange and my phone refused to accept it so I phoned orange and they took the number of the top up card and told my it had not been activated and that I would need to get a refund from the retailer. So I took the card back to the retailer and got it exchanged and when I keyed the card details into my phone I found orange had already credited my phone for the other cards value.