Yup. Same.  Many calls over past month, leave no message or no one there at pick up. A callback gets  a 'female voice' that says,"This person has a voice mailbox that has not been set up yet.'  
ID say wireless caller

Ditto on your post Wattapain.  So tired of these annoying people.

I have received several calls over the last few days from this number.  I did respond once by pressing 1 and was advised that the company name is United Conservation Group which is doing in home energy use studies to assist homeowners, through a government assisted program to reduce energy costs by 30 to 50%.

Unfortunately, I scheduled an in home appointment for Thursday, 03/21/2013 at 6pm.  I have called this number several times, looked for this company online, and checked the Better Business Bureau in Dallas and Tarrant Counties, Texas, but have been unable to find any information or response.

Thanks Jim, that is more than I good find, I was really hoping for a local location so by cutting their phone lines I could get these call to STOP.

I get calls from them everyday. They never say anything. so why does it call everyday??