My question involves criminal law for the state of: illinois/alabama

a couple of moths ago i was caught shoplifting from a wal-mart in illinois, and did all the courth things and now i am on diversion. my question is in regards to the civil demand letter.

I have recieved my first letter from the law offices of Michael ira Asen, who claim that this is my second letter i should have recieved from them. In addition i recieved the letter today and in the letter they said i had 10 days to pay from the date of the letter which was february 7th. as today is the 22nd I am past that date. What should I do, and is this the real collection company as the letter i recieved from Wal-mart told me to expect it from a different firm, so what am I to expect from those who have gone through this before, or at least know more about the law firm.
In addition i was in illinois when i was caught on my winter vacation, but am now in Alabama for school, how will that play affect items, and i am over the age of 18.