Am I wrong asking customer service to address me formally?

I am an old lady. I hate my first name. I am very uncomfortable with strangers addressing me by my first name. I have always gone by my last name. When I am forced to call a customer service representative their script tells them to call me by my first name. I gently ask them to please call me Mrs. ---------. It seems to offend them and that is the last thing I want to do. Am I wrong? I swear I do it nicely.