Problem with bluetooth hands free and iphone

I'm having trouble with my iphone 6 and my bluetooth hands free in my Mazda CX-9. When someone calls me while I'm in the car, the screen on the car displays a total different person than who is calling me. It was occuring occasionally when I had my iphone 4s but now it is doing it all the time with my iphone 6. Has anyone else had this problem and any ideas to fix it?