Using pressure and threats to obtain more money
After my booking was confirmed, I was called back to change flights because the initial flight was full. After changing my return trip and confirming this, I was called again to change my outgoing trip. They wanted me to pay over $150 extra even though the new booking was inconvenient for me and it did not allow carry ons on the plane without extra pay. I even think they lied about the flight being full since ultimately, the return flight was the same as the one I originally wanted.