Use the numbers listed on your copies of the credit reports. They all require you have their report # or file # to start a dispute. If you've pulled a merged report, you'll still need the individual CRA paper in order to have a useable file number. As for success, depends upon the argument. Most will take a couple of standards (not mine, never late) without a fight. Personally, I would use the online systems. Each CRA now has them and just dispute as many as you need....
