Hi
I have recently joined BT and as part of the package was a £50 reward card.
When i log in it takes me straight to my BT account and there is no option to claim the card.
Any help would be welcome guys
You can not claim the card until your 14 day cooling off period is over.
As @gg30340 says you need to wait the 14 days after your services go active.
If its been more than this I would contact BT billing directly:
Broadband | BT Help