Never received any letter from them.  Just a daily phone call from the same number since the middle of 2013.  I've never answered so I don't know what the message is.

In the past three years I've borrowed money to build a house and buy 3 cars.  My credit rating is above 800; so there are no outstanding debts on my credit report.  This company will attempt to blackmail people into giving them money under the threat of filing false unpaid debts against your credit report.

Most the time they do not know who they are calling.  They want you to return their call so they can get a name. They will then search your credit history and search for a credit card bill that can go back 10-15 even 20 years ago.  Now they have a name and credit history that they will exploit.  They will claim you had a credit card debt from 1995 that you never paid, and they want proof that you paid it. (Who keeps a paid receipt for over 20 years)?

Now that you talked to them, they can legally document that they contacted you and that you are a deadbeat; then they will falsely file against your Credit Report in an attempt to blackmail you into paying them on some bogus bill that you do not owe.

I don't want to file against them because I don't want them to know my name.  Call blocking is easier but I do appreciate all your advice.