I'm getting these annoying calls also.  They all start with the area code 205 and prefix 868 . All but 1 were from birmingham alabama. One was from calera,ala.  They are calling several times a day Some calls were within 15 minutes of each other.  I never answer and let my answering machine get it.  They always hang up.  The latest one actually had NATIONAL CEMENT on my caller ID(205-868-4340) The others said Birmingham Ala. I tried calling back some of the older numbers on my cell phone hiding my number, but most had a recording that the number you have reached is not in service(not sure if they are telephone company message or company recording made to sound like phone company message) On one number (205)868-4550,a person answered with a name of some financial co during the day.  When I called at night, it was a voice mail for some guy named Jeb Park.  The last number had a recording for National Cement Co(205-868-4340). I'm guessing  telemarketers from Alabama.  The numbers I have gotten calls from are
205-868-xxxx (xxxx=4390(national cement),3760,3690,3800,3780,3220,3190,3360,4550(Jeb),3920,3700,4010,5510,
4440,3430)