call received...no sound on other end when answered

This number tries to call me as well. no one on the other end. Are they just checking to see if this is a good number for another number to call and sell something?

January 24 th 2011  
These people called me at 6.44 pm AZ time and asked if I wanted to have my roof on my home inspected due to the hail storm in October and that a inspector will be in my neighborhood . I told the lady that my home did Not have any hail damage
and that the hail damage to homes occured in the north and west part of Phoenix.

Caller said he was from Travel Agent and wanted to talk about our resort, that we had time that we were we were going to lose. Hung up on him.

Called my cell phone at approx. 9:10am EDT Fri. April 22; didn't recognize the number so let it ring through to voicemail. Caller left no message.