I think there is something not right with their booking system... I am very very careful with booking flights and I always double check the dates and the flight times when booking.
I was directed to Opodo from kayak for the dates and times that I wanted (I checked). I proceeded to enter my passenger and payment information. After payment, i received a confirmation but one of the return flights was different resulting in 13-hour layover time (in the original ticket it was 6 and a half hours). I used their 'free cancellation within 1 hour" option and cancelled it immediately online. They promise to fully refund me within 10 days. My advice is don't use them but if you decide to, then sae all the screenshots at every step of the booking process.