I remember receiving a fair amount of threatening letters about the TV licence as a student, shortly after I moved out of my parents place to attend university.
It was extremely confusing and made me a little anxious.
Not only did I not own a TV or watch TV of any kind, even online, any effort to make this clear fell on deaf ears and the threatening letters continued.
Eventually it became normality and I learned to drone them out of my conscience but it was such a strange concept to me back then. I'm just thankful I never got anyone knocking on my door demanding to check my room.