I've been getting this on my cell phone too. I called this number back via my office phone. The recording just states something along the lines of "if you wish to be placed on the do not call list for the number that just called you, please press 1 now". Then silence. I pressed1 and got "your request will take 48 to process".
if you have an iphone, you could block this number. I got calls from this number a few times a day. Once you block it you won't even know they are calling
I have had several calls from this number. They never leave a message. I think it is a service trying to validate phone numbers. I saved it and changed the ring tone to "no ring" so when they call all I get is a beep that I missed a message.