I got a ticket from Zürich to Athens for May 2022 and paid an extra 19 € per person to have a changeable ticket. I have also bought the OPODO prime. I always checked my account to see if the ticket changeable is and my OPODO account showed me always that I can change my travel time one day before the departure time. However, two days before the departure suddenly the OPODO showed me that I cannot change it anymore online and I need to call them. They told me that the ticket is not changeable. How is this possible? the ticket I paid extra to make it changeable and three days before departure time they told me that it is changeable but as I wanted to change the date, OPODO did not allow me. They made mistake and did not take responsibility for their mistake. I lost about 600 € due to the mistake of OPODO and they do not refund my money or do not offer me any other ticket. I attached two files, one shows that I am allowed to change my ticket one day before departure and another one (2days before departure) is showing that I have not allowed to change the travel time.