Ugh! So you need to keep monitoring it.It states online that the item MUST already be on your credit report to dispute it though..........meaning if I send them a letter now, they will not acknowledge it I believe.
I don't know whether it's state or federal law but I believe you are entitled to one free credit report per year from each of the 3 credit reporting agencies.
If you spread them out over the year, i.e., do Experian first, do Transunion 4 months later and Equifax 4 months after that, you'll get all the reports over the 12-month period. That way, you should see if any negative reports pop up.
Chances are, if they show on one report, they're on all 3 and at that time, you can submit your letter.