Both are possible, but "mevrouw" is a slightly more formal or respectful term. It is also used to address women (like ma'am or miss) or used together with a last name (Ms. Smith, etc).
Why is "listens to you" (as opposed to "hears you") incorrect, and how would one say the former?
To listen to someone means to actually pay attention to what they are saying. Hearing someone could mean that you are hearing the noises/words being said but you do not understant or pay attention. "To listen" is translated to "luisteren"
i'm not sure if this will clarify, but i believe that listens implies a direct conversation while hears could also be conversation but is more likely someone calling someone else.