Sorry to say it but the airline will not compensate, nor should they.
It is always the responsibilty of the passenger to ensure he or she is in compliance with all requirements such as visa's--in other words to have the proper travel documents. A "he-said, she-said" type of scenario will not alter that...remember the old maxim, "Ignorance of the Law is no excuse".
The airline has to enforce these rules to be in compliance with whatever requirements the destination country happens to have.
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