AFNI, Inc Zombie debt T-mobile bill trying to get nearly $200 Bloomington, Illinois

I'm so glad I learned to research the companies trying to collect debt from me before assuming that I owe them money. I did have a T-Mobile account about 8 years ago, and I did stop paying it and it went into default and the account was closed. Then I paid it off, hopefully legitimately, a few years ago. 

Now I've gotten a letter from AFNI, Inc offering a settlement of $198, half of the alleged balance I owe. 

The letter from them is less harassing and demanding than other collection letters I've gotten from various companies, but after a quick Internet search I see that means nothing. It took about 30 seconds to discover that this company is a scam. It would be so easy to say all collection agencies are scams, but really they serve a purpose when they are legitimate.

I am fully aware that debts need to be paid and I have a responsibility to make financial restitution - i.e. they don't want my money, they want their money back. Totally understandable. HOWEVER, dredging up old and expired debt to make a profit is just bullying and harassing. 

I am sending them a debt validation request tomorrow. They will be mad, just like the last one was (Blackmon, Lafyette and Associates, FYI) but they will go away.