they keep calling me and hanging up

My guess is someone is using a geriatric collection agency

private investment very secure sounding

Told them numerous times to take me off the call list. They are calling about car insurance - call three, four or more times per day!

This was a legitimate call from Thoroughbred Research. They were calling to follow up on a call I had made to the gas company regarding a gas emergency. They asked me if I would voluntarily do a survey based upon the customer service I received. They were very courteous and it took only 10 or 15 minutes, and I wanted to give the feedback. They called two times about three hours apart, once from this number and once from a different one. I wasn't home the first time.

Life Insurance solicitation