I had a slightly similar travel agency stuff up. Was going to BKK in Sept and get to check-in, suddenly there is a big problem with my ticket. Our company travel agent, who has booked at least 20 flights for me, booked a child's ticket instead of an adult one.

China Southern checked me in then noticed there was a problem. Lots of going back and forth the the agent and multiple staff at the airport. Difficult to resolve because CS wouldn't give me a boarding pass until the agent changed the ticket and the agent couldn't change the ticket because CS had checked me it already. Eventually got on the plane but it took well over an hour to sort out.