Monobank blocked the card and does not answer why

You need to write a written request to Monobank with a request to provide an explanation of the reasons for blocking your card.

Pursuant to Article 7 of the Law of Ukraine "On Appeals of Citizens", appeals, duly completed and submitted in the prescribed manner, are subject to mandatory acceptance and consideration. It is prohibited to refuse to accept and consider an application with reference to political views, party affiliation, gender, age, religion, nationality of the citizen, lack of knowledge of the language of the application.