UPDATE: Interesting, received call on our landline from 904-719-6883 on March 17, 2017 at 5:56pm. Same phone number that called my husband's cell phone this morning, twice. This time, though, I can block it, for free. Seems they are spamming an area.
I got one this morning but was on the line with a call I could NOT disconnect from so I let it go to voice mail. The voice mail was blank. It is possible that this number is a robocall from a computer and logs if you answer or not. Then the numbers who answer, and the times the calls were made, is either given to a telemarketer or sold to other services so they know when you are home and call you for their services.