If I could leave 0 stars I would. Do not book with this company! Booked my airfare home to the States with a US credit card (currently living/working in the UK and traveling home for the summer.) Received booking confirmation details and payment authorized emails after booking. Immediately received a call from customer services checking if I wanted to upgrade my fare. No thanks - all set. Two weeks later, receive an email saying my payment has not been authorized and my flight/tickets have been cancelled! No warning, no email, no phone call just cancelled. But the payment was taken from my credit card the day of booking. And the agents spoke to me immediately after booking to ask about upgrades! They seems happy to take my money then... Called customer services to ask why my flight was cancelled and they said I need an authorization code from my card carrier - so I call them - internationally at my own expense. Card carrier says there is no authorization code to give, but that TravelUp has successfully received payment two weeks ago and if they have an issue to contact them for the verification code. Call TravelUp again. After being put on hold, talking to several different agents, finally one comes on to say that without verification code, they cannot confirm my tickets. Nothing else to do - "it's just our policy." So two weeks later, Travel Up has had my money for weeks and cancels my tickets without warning because of an inexistent code. Now flights are more expensive and I can't pay for new ones until TravelUp refunds the money they've had for weeks. What sort of business model is this? They clearly received payment from me and sat on it for weeks without contacting me to discuss this non-exsistent authorization code. Will never book with them again and advise you not to trust this business!