National Diabetes Association Repeated unwanted phone calls, even after asking to be removed Internet, Internet

I originally received a call from the National Diabetes Association about 6 months ago.  They start off by asking your name, you are a diabetic correct?  I asked where they were calling from again.  They told me.  The gentleman said they were calling all medicare qualified diabetic patients to assist them with their diabetic supplies.  Well, that's where I stopped him.  I am not on medicare and no where close to being on medicare!  I asked him to be removed from their calling list.

The next week I received another phone call.  Stopped this person before they got everything out.  Told them I was not on medicare.  I had already asked someone to be removed from the calling list and could they please make sure this happened.  They apologized and assured me they would.  Thought that was the end of it.  Boy was I wrong.  The calls continued off and on over the next several months.

I received a call yesterday and told the lady on the phone I was not medicare and had asked to be removed from their calling list.  Again I was assured I would be.  I received 2 phone calls about 10 minutes apart this morning.  I asked both times to speak to a supervisor.  I told both of the gentlemen on the phone I had asked for my name to be removed from the calling list.  They kept on talking over me and then hung up on me.  I am at my breaking point with this company.  Sometimes a number will show, other times it comes up unknown and other times it shows as a +1!!

If anyone has any suggestions, I am open for them.