I will share with you a little known secret.
If you have no ticket to the Alhambra go to the entrance of the Alhambra.
Don't get into the queue for tickets.
To the right of the entrance is an area with yellow machines.
Put your credit card into the machine and buy a ticket.
The people in the queue are wasting their time but nobody tells them.
I spoke to someone who did this yeaterday and they got a ticket for 5pm this was at 11am.
On the website the tickets were sold out.