Salary getting cut in half, benefits taken away, being harassed. Is there anything I can do?

I was sought out by a company that wanted to hire me right away for 80k a year plus benefits. It was more then I was making at the time so I accepted. I did not sign a contract or anything stating what I would get paid. They had a random inspection and said that they needed someone with a certain license that I didn't have (They knew I did not have this before they hired me) so they said they were hiring someone else and that they will have to cut my pay to 45k with benefits. That was way less than I was making at my previous job. The owner of this company has been harassing me saying that if I wanted to leave that I would be doing them a favor because they could find someone to that would work for half of what I was getting paid. They called me into the office today saying that they want to take my health insurance away now. They are making harassing remarks to me because they want me to quit I am assuming. Is there anything I can do ? They are treating me so extremely bad. I am a Marine Corps Veteran and have never been treated this badly in my life. I am stuck there until I find another job. Please help me. Is there anything legally I can do to them for treating me this way and for cutting my pay in half as well as them taking my insurance away. Thank you