How to handle this collection agency issue

About a month ago I received a letter from a collection agency stating some internet phone service who I have never used says I owe them 22.54 for some unpaid bill, which is not possible. I requested the collection agency ask them to send me a itemized bill showing exactly what I owe them for, and it has not arrived. My question is, does something like this automatically go as a negative on your credit report if you don’t pay, even if it is a scam? Do you have to petition the collection agency, or one of the credit report companies? What is my recourse?Thanks!

Send anothyer letter, send the letter both certified and reg 1st class mail. Say that you are disputing the bill, and you’d like a copy of it. State you are making this request under the Federal Fair Credit Reporting act
http://www.ftc.gov/os/statutes/031224fcra.pdf

and the Fair Debt Collection Pratcices act