Don't use. You can get trapped with your booking.

I booked my tickets and paid with credit card. Everything went successfully, received a booking confirmation. But later they sent me a message that my payment was unsuccessful. I tried to pay with the payment link they sent me (this method is used by many ****s by the way). But it failed again. I received the booking cancellation and tried with another credit card next day. Same story. What if available tickets are gone now? Remember, if you buy tickets with another company now you don't know how many tickets you have. You are trapped, at least until you receive a cancellation message. They took my credit card details and they can deduct the payment at any time when their system will start working. Do you think the refund is going to be easy? I tried to contact them, still waiting... Stay away from Travelstart.