Since 2004, EU citizens have had the opportunity to receive compensation from airlines if flights are delayed more than 3 hours. Over the past few years there have been more and more services offering to run the cases for you.
These services are basically free only until they win the case and from there take between 20-25% of your compensation.
This means that cases where you are entitled to compensation of 600 EUR per. passenger, then some of the claim agencies will take about 150 EUR.
In some situations, it only takes a few minutes of work, even winning a case where you are entitled to up to 600 EUR. Therefore, we believe that you should always start the case yourself directly with the airline and go around an intermediary who takes 20-25% of your compensation.