I just went through this yesterday when I called with a question about Test Track at Epcot. The initial wait time said it would be 11 minutes, which was about right. After I asked my question, the cast member said she would have to contact someone else and for me to please hold. I looked at the time and after 30 minutes I hung up, thinking she had forgotten about me.
I called right back and this time I used the "Press 1 to leave a callback number", saying the current wait time was 29 minutes. After about 20 minutes someone called me back. After I asked my question again (different person this time) she said she would have to research the information and to please hold. This was around noon and I was determined to stay on the line this time if I had to wait until dinner. 40 minutes later she returned with the information I needed. I do not blame the people who work the phones at the call center for the long delays since I'm sure they are doing all they can with the staffing problems.