You had an old bill that 8 years old and it just turned up now?  Well that is an excellent FCRA case.  Then you also have an FDCPA case as well.  Do not pay that bill, go see a lawyer immediately as these people have just commited a crime and you should sue them as well as report them.

Federal law (FDCPA) requires them to send you a letter (US MAIL ONLY) postmarked within 5 days of their first contact that contains their name, physical address, the creditor’s name, and the amount of the alleged debt.  It also must contains “mini-Miranda” telling you that it is an attempt to collect a debt and that all information will be used for those purposes.  The one other important thing that this letter must also have in it is that you have a right to dispute the debt within 30 days of receipt of the letter and if you do so, all collection activity must be stopped until the debt is verified.

Read up on your rights here, get template letters to send and also make a complaint at this government site: http://www.consumerfinance.gov/

Also file a complaint with your State Attorney General's office.
List of State AG’s offices:  http://consumerfraudreporting.org/stateattorneygenerallist.php

You need to go out and get a consumer lawyer to sue them on a contingency basis (no money out of your pocket) and let them pay you for the harassment.  If everyone did these three things, these crooks would be bankrupt and we would all be the richer for it.  Use these web sites to find an attorney in your state that will probably take the case on a contingency basis (no money out of your pocket up front):  http://www.consumeradvocates.org/
http://www.consumeradvocates.org/find-an-atto ... tates_value=All

FCRA: https://www.consumer.ftc.gov/sites/default/fi ... porting-act.pdf