Open Question: A question about collection agencies?

I received a collections notice from an old cell phone account that was bought by a collections agency (www.afnicollections.com). The thing is, it's from an old (over 3 yrs) account. It was back when I was in college. In the collections notice, it states that they are willing to settle for a mere $25.00. The thing is, I wouldn't be paying the original creditor, but the collection agency. I read that if I were to pay this collection agency, that this could potentially bring down my credit score and open up my credit to credit hits that will bring it down. My current credit score is mid 700s. I don't want it to go below 700. Answers are much appreciated!!