From the Crystal Website :-
Crystal wrote:For holiday payments
To make a payment please call us on 020 8939 0726. We're open 7 days a week.
For travel documents
If you're due to depart on 10th or 13th of December, and you haven't already downloaded or printed your tickets, please call us on 020 8939 0726 and we'll ensure you have everything you need.
From an article on TravelMole :-
A spokeswoman said Crystal had been advised by some customers that they were seeing other clients' travel itineraries when they clicked on a holiday booking link which had been emailed to them. As a result, it had disabled that area of the website to investigage the cause.
"We are obviously appreciative of the customers who acted promptly to advise us of the issue," she said. "We are also urgently taking steps to ensure this situation will not be repeated."