Turkish Airlines Prague Airport Boarding Staff Issue

Hello, on my flight from Prague to Istanbul with PNR: R7R37K, the boarding staff at Prague airport informed me that my cabin-sized luggage would not be allowed on the plane and would be sent to the cargo hold. Despite my insistence that my luggage was cabin-sized, they displayed indifferent attitudes; however, my luggage was neither measured nor weighed. When I asked why it was not allowed, I did not receive any response. Upon boarding the plane, I explained the situation to the flight attendants, and they agreed with me. When they went to retrieve my luggage, they were told it had already been sent to the cargo hold and could not be retrieved. The flight attendants tried to assist me, but the important issue here is that, despite flying with Turkish Airlines, I felt a prejudice against us in Prague, and this is not the first time. Two weeks ago, I heard that a friend of mine was also spoken to rudely.