I'd support the Children's Hospital of Wi. / Froedert assertion. I've been chatting with their HR recently. I'm curious, though, why they wouldn't leave a message.

It's a bill collecting firm. I frequently get calls to my new number from collection firms. I've figured out the person who had this number before me must have skipped town and disconnected there number. I get calls every day. This is a bill collector.

I got this call and they hung up right as I answered and I tried calling the number back and it said it wasnt a working number....WEIRD

Again they called my cell.  No response.  No message?

I received a call from this number and it was in response to a job application I filled out.