Family drama

So I need advice so my grandparents helped me get into my apt and get furniture but every month I pay all my bills well my bf came down to visit me n he has been here maybe a month and he is black which my grandparents disagree with but when my grandma comes over she tried to come in with her key without knocking she says rude things or when he is not around makes comments he needs to pay bills or leave how can I not be rude but let them know this behavior needs to stop cause its disrespectful to my company in my home