I had tried to book with Trip.com last 2years and 99% has been failed with the booking when you come to the payment. I only manage to book 1 ticket for my partner travelling from Vietnam to Thailand.

Once I change to Go To Gate, Expedia or Vayama any of those sited then the booking confirmed and issue ticket with no problem, of course the fare was 10 to 20 euro higher on those site.

Trip.com just lure you to their page and waste a lot of your time. Even the amount that Trip.com wanted was on hold in my Revolute account and after 30min the amount was returned, so I find it strange they said the payment didnt went through.

As far I know is only Expedia show booking class in their system.