Bay Area Collection Services Collection Scam Antioch, California

Today marks the second call I have gotten from Bay Area Collection Agency.  The first was on my cell phone, a non published number that there is no way they would be able to connect it to my name as they ask for Jennifer which is my name but it is in the name of Raymond.  I thought I had this cleared up when I made it clear that I had never been to Duncan Regional Hospital by ambulance or shall I say ever at all.  I gave them my birthdate which was not what they had on file and they assured me they would take me out of the system.  Today I got another call, this time to my home phone which is also not in my name.  I once again cleared this up.  I do not know why they would be calling me.  I think there is someone out there with the same name I have but how they would connect me to this is beyond me.  I am thinking this ambulance thing is some kind of a scam.  I told them that if they call back I will be forced to take some kind of action.  What can I do to stop this?  There is not a chance that this is me they are looking for and I have no clue how they got my information.  I would think that if a bill was turned over to collections there would be finding information.  I work for a hospital and they are required to provide such information along with a copy of their drivers license.  Any ideas?