So, only 1 member got money back?
Are you sure, that you got money back? Already on your new card?

any ideas? Anybody tried to send there a letter? complain, real paper complain to ask them to write you a good answer why is your card blocked and who will pay for airtickets and for hotel if you go to Poland.

It seems like only if you have more than 500-1000 eur on your card - you go to Poland.
If less... so nothing? It costs 200-300 euro for European to go to Poland. tickets, hotel. This way Mbank is stealing money.

IMHO, we need to send not email, only real complain letters could help. They have to answer why they block your card and why you have to go to Poland.
They have to answer on each letter.