Southwest Airlines Software Engineer interview questions

Sent in application and then got an email form a recruiter asking for available time for an interview and a copy of my resume. During the phone interview I had asked the interview to repeat two questions because i could not hear or understand the interviewer. For one of the questions, the interviewer said in a very quiet voice, "Oh, maybe you don't know that yet." and that one one of the questions I could not hear the interviewer at all. The interviewer quickly went to the next question after saying that. I felt that i did not go to the next phase because of that question.