The Transaction N° is NOT the reservation number. If you are asked to call 34-91-537-91-78 do so IMMEDIATELY . I had a 08:30 reservation, or so I thought, (they debited my credit card!!) made on March 1, for May 12, but today (Mar. 11) I called: I have no reservation, and must take a 14:00 entrance time.
I got an 11 digit-2 alpha reservation number. Lesson: make your reservations early, during Spain business hours, call immediately if there's a problem. To add insult to injury, the price for two tickets went up from 17,76 € to 21,30 € during those 10 days!