Mojoryezen:
If you haven't done anything yet, save yourself a super huge headache and possibly more headaches by just not doing anything. You could try disputing it online - they may or may not verify it. If it comes back verified just leave it.
It will drop off 04/2008.
Alltel will drag their feet and you will be in April 2008 and maybe even May 2008 or later still trying to get this taken care of.
I dealt with Alltel for almost 7 months before I finally had to go to the BBB to have it removed.
If you are not careful, (they probably don't have the account info anyway) they could accidently on purpose reage or change info just causing you more headaches.
10/01/2017 myFico EQ-778 TU-793 EX-781
11/01/2017 myFico EX-799, Barclays 11-4 Reported: EQ-796 TU-826 EX-799