This number keeps calling me and hanging up. When I call it back, a recording says the number is not in service.

THIS IS A PAIN IN THE ///   MANY CALLS BUT BY THE TIME I GET TO PHONE THEY ARE GONE.
THINK TELA MARKET...I DO HAVE DO NOT CALL LIST ON PHONE...

Got 2 calls from them on November 12, 2012 at about 9:27 am and then at 11:50 am. I answered the second time. No answer.

I got a call this late morning at about 11:40 a.m., November 12, 2012.  They didn't leave a message so I called that number to just see who it was...no answer.  FYI.

this A..e keep calling at all times

The FTC just took down 5 of these scum suckers. Obviously they have a few more to go.
http://www.ftc.gov/opa/2012/11/robocalls.shtm

What To Do When You Get an Illegal Robocall; http://www.ftc.gov/bcp/edu/microsites/robocalls
1.    Hang Up. Do not press 1 or any other numbers to get off the list.
2.    Consider blocking the number
3.    Report it at http://www.fcc.gov/complaints
4.    Report it at https://www.ftccomplaintassistant.gov
5.    People should continually file complaints with their Attorney Generals office.
Register your phone numbers online at http://www.donotcall.gov or call (888) 382-1222 (must call from # you want removed).

I have greatly reduced the number of calls to my cell phones by going to my carriers website (Verizon) and they allow me to block up to 5 numbers for 90 days. Since these scum change numbers every 30 I have had a very peaceful time. Call me once shame on you, call me twice shame on me. I also put it in my contacts list under Scum Suckers and assign it NO ring tone so at least after the first call they won't bother me anymore (I have filled all of the numbers in each and am up to Scum Sucker 47 now). This is only a whack-a-mole solution however it is the only one I can offer.
If you want to stop these calls then you need to dry up their revenue source. Your phone company is charging you a fee for caller ID. Your phone company pays the scammer for sending their caller ID information. Your phone company pays only a fraction of a cent per call and you pay $5 to $15 to your phone company. The scammers send out millions of calls per day which amounts to a significant amount of money however your phone company is charging a large amount to millions of customers. This may have something to do with the phone companies inability to stop these calls. You can also see why the criminals keep calling even though they know you won't fall for their scam. If someone does make the mistake of answering the phone and falling for their con then it is just icing on the cake for them. These people are the lowest form of filth on this planet.
In order to stop this we need legislation making it illegal to charge for caller ID. If a phone service wishes to operate it would need to provide the caller ID at no charge to other phone providers and to it's customers as part of the service. Here is the $50,000 solution that the FCC is looking for and it doesn't cost anything.
Many of the disposable numbers come from Pacific Telecom Communications Group and they are currently under investigation and in the midst of various lawsuits. (The principles involved have been part of actions by the FCC under other business names). Here is an excellent blog site that I found that explains how this company is getting away with this activity.  
  http://telemarketerspam.wordpress.com

I had four this morning. S****y telemarketing pings, checking to see if there's a person at the other end, I'm sure, so they can add it to their auto dialer, which is ILLEGAL by the FCC to market that way. If there was only a way to get back at these people with the system, which has us locked out of being ABLE TO DO ANYTHING AT ALL ABOUT IT. Furious about all the unwanted intrusions.