to do the full game you need to do all these steps
1. buy the game(sounds like you did this)
2. enter the retail key(not sure you did this)
3. select a renewing subscriptiopn (required)(this option shows up after you enter the retail key)
4. enter how you plan to pay for the subscription once it starts(also required)
5. wait for cryptic to validate the payment type. (they do it in batchs so time varies)
then your account will be active withthe 30 days subscription bonus.
if you used a credit card or paypal then you wil not be charged for the subscription until after the 30 day bonus.
if you use a gametime card then the 30 days will be added to the time of the gamecard ie 30 day gamecard + 30 day bonus = 60 dayes before you have to enter antoher game card to play.
if you skip any of these steps then the game will not be active
if you did all the above steps and still can only play the demo then you need to open a ticket with billing.