Statute of limitations is not the same thing as the FCRA compliance date.
The statute of limitations is the amount of time a creditor has to sue you for the debt. (This varies state by state.)
The FCRA compliance date is the date an account will be removed from your credit file.
The FCRA compliance date for collection accounts is 7 years after the date of the first delinquency with the Original Creditor.
Even if the collection agency sells the debt to another company, the FCRA compliance date remains the same.
There are instances where collection agencies illegally re-age accounts, moving the FCRA compliance date. If this occurs, you have to contact the credit reporting agencies, the CFPB, and the FTC. http://www.creditfirm.net/blogs/reaging.html