Letter from an ex--what do I do?

Today I got an email from an ex. We haven’t spoken in four years (and I have no need to start now). Today’s email said:

“I have a letter I would like to send to you. However, I wanted to ensure it will be acceptable to do so prior to mailing it.”

My first reaction was, “why send an email to ask if you can send a letter?” I would love to hear the fluther wisdom . . .

While I can think of a number of responses, I would love to expand the choices with your help!