To start with, my son booked with WizzAir, not me. On 28/2/2020, he tried to check in for his flight. The would not let him because he had OVERPAID 3,6EUR... I really do not know how this is possible but any way, in order to proceed they asked him to contact customer service. To make a long story short, eventually there was only ONE OPTION. Call them and be charged! Otherwise he would be denied carriage!!!. Imagine what would have happened if he had underpaid (how is this possible?). So, he asked me to call them to resolve it. I called their Greek line and they answered in English... One way or the other, I hope that we managed to get him checked in. I do not know whether they learned how to return the 3,6EUR. I know that in the process their customer was left with no option but to be charged heavily for a phone call to their customer service. (In excess of 10EUR according to a message that I received from my phone company, and I do not know if anything else follows!) - All of the above can be shown on screenshots that I have taken.