If you call them back, you get a recording, and it's the environmental group of WI. You can then have your phone number removed from the call list without talking to anyone.

I am so aggravated with this number calling me and no way to track it.  My phone doesn't let me block calls or I certainly would.  

Wisconsin Environment im pretty sure. Get several calls a week. Donated to them last year. Should probably tell them to take me of the call list but I'd rather assume they'll get the message by me continuing to ignore them.

It is an environmental advoccy group from Madison. I donated to them once 3 years ago and now they are phone-stalking me.

Keep getting calls from this number, no message.  Same time of night.

Never leaves a message, calls 1-2 times/day.  The most recent was SUNDAY at 9PM!!

Called with hang up filled directly by callback

Pretty sure its UW Hospital cause I so owe bills.

Called and hung up -- 8:10pm on a Sunday.

Yep, its defs an environmental advocacy group. They called me from another number as well. Also left no message.

Just called at 8:45 pm. Left no message.

Called twice in four days but left no message.  Might be environmental advocacy group based on other comments.

It's definitely not UW-Mad Foundation.  
Drives me crazy--thanks for reporting that it is an environmental advocacy group.

Have gotten three calls from this number in the past week.
Just called the # back and the recording indicated this number is for an environmental advocacy group.

This number calls me nearly every day, sometimes multiple times a day, but leaves no message. Very annoying. It is from the Madison area.

Calls many times a week, sometimes after 9pm.
Perhaps political call?  Maybe UW-Madison foundation looking for donations?

I'm thinking this is a political call? Calls, leaves no message.

Called but left no message