Annoying calls. Constant and annoying.

Multiple phone calls --- they never say anything --- 2 to 3 times a day to my OFFICE number at a hospital!!  I've been leaving my phone off the hook when they call for about 10 min so hopefully it ties up their line and they'll stop!!

I answered and no one said anything!

Repeated calls with no one saying anything

You have to stay on the line for a minute in order for someone to say something.  I was about to hang up.  Claims it is some census agency wanting to ask questions about health insurance, health care, etc.  The lady asked if I had a few minutes to answer questions.  I said no I'm at work.  Said she would call back later.  I asked her not to call back, so we will see if that works.