Chicago Tribune / collected money twice!

One evening I had 2 teenagers with credentials come to my house asking for donations of $15 towards "The Good Shepard Nursing Home" for those needy people to be there and can't afford there stay. Chicago Tribune had some kind of assistance of a kind of match in donations and as a thank you (supposedly) the donator would receive a 3 month subscription. Then for my surprise a few months later I get a collection bill for $16. Here it is a brutal SCAM (the stronger ones against the little ones). Be aware!!! Don't allow to happen to you. I've learned my lesson the hard way when I was just ready to help the needy.