Originally Posted by intuition

I am pretty sure it is illegal to have hidden rules that were not disclosed either at time of purchase or in a order confirmation. So if you don't want to let it go, that is the route ahead. As going to court is costly and risky, I only see two options. Either report to consumer protection agency and hope they open a case (something like Finnair "not conducting business according to customs and traditions" or "doing false / misleading marketing" ) or name&shame. Neither is guaranteed any result.

I guess the lessons learned by me is to require CS to send complete fare rules before booking anything using Finnair channels...