Who called from 5150000000

Started receiving week of July 23rd- answered first several, then let go. Seems to call approximately every 1.5 - 2 hours. Guessing this is survey related, perhaps political. Not certain how to get this to stop.

Started receiving this call on July 27th.  Calls about every 2HRs.

I think it's a fax machine from Iowa State University?

We have been receiving these calls since late July. The number appears to be a fax machine at Iowa State University. No idea how to stop it.

Same deal - calls 3 or more times a day, answer and dead line.  If this is an Ia State #, they need to stop it.

I've been getting the same calls, so I researched the number and I found message board.  I called Iowa State and they checked their campus switch board for phone calls to my home telephone number from on-campus phone lines and found no records of anyone on campus calling my home.  She said all of the phone calls from campus are routed through the switch first...so they have every record and found nothing attached to my home number.  Must be coming from somewhere else.  It certainly is bothersome, isn't it?  I will post more info. if I find anything else out.  Good Luck!!