I had a collection from RJM claiming I owed on a book club. Since I knew this couldn't be mine (never joined a book club in my life), I decided to start with it. I disputed with EX and it came back verified. So I checked out a few sample DV letters to get an idea of what I needed, then wrote one up and sent it out CMRRR. As soon as it was signed for, I disputed with EX again. RJM deleted yesterday.
One down, three more collections to go and then I only have Cap1 to deal with.