RJM Acquisitions LLC changing dates on my credit report? Syosset New York

Earlier this week I received a letter from RJM Acquisitions LLC claiming that I purchased books from a Good Cook Book Club. I called them and spoke to an agent, explaining that I had never purchased books from any company and that this was a case of fraud. The man was extremely nice (suprisingly) and explained that he was closing out the dispute and it would be removed from my credit.

Now my question is - upon reading over the letter I rcvd from RJM, I noticed that it said the following:

Date account opened - June 6, 2003
Date RJM Purchased This Account - February 11, 2008*

Noticing the * I looked at the bottom of the letter for an explanation, and it reads as follows:

* When RJM reported this account, EXPERIAN told us that we must use February 11, 2008 (the date RJM purchased this account) as the opening date rather than the original opening date of June 6, 2003.

OK, I'm confused... I thought this was against the law? I thought that creditors had to use the last date of activity or something like that? I'm still trying to gain understanding in to all of the rules and such so I apologize for my ignorance, but can someone explain this to me?

I am happy to know that RJM is deleting the debt from my credit report, but I just want to be informed for next time....

Thanks!

My_shell
Tucson, Arizona
U.S.A.