Hi, see it's your first post so WELCOME!!!!!

Since you did not answer to the letter and try to claim your meds you shouldn't have anything to worry about. I know personally a few of my friends who have received these "love letters", myself included, and ignoring them is the best route to go. You won't here from them again, and for 60 pills The MIB'S are definately not going to show up at your door.
Hope the info helps-
Summer