I have received a voucher from them with one year availability (after a long battle with their Customer Service).I have booked a flight and had to pay a 30EUR difference.When using my card, I instantly received a message that the carrier increased the fares and the asked me to pay 3×the initial difference.I've made a search again , received the same smaller price difference but when I tried to pay for the fights , they increased again the flight fares. I have checked different routes and I got the same story.I wouldn't recommend this online agency to anyone so think twice before booking with them. Their so called algorithm is working only in their favour.