I called Experian to try and clean up my reports, since I'm unable to do it myself online for some reason. The rep disputed an old Amex chargeoff that was IIB in 2017 and it came back and updated for this month as a negative that dropped my score 12 points 
what can I do?!?
EDITED TO ADD: That account was disputed in error. There are accounts that were IIB that are actually NOT mine, but after they showed IIB/0 balance I just never worried about it. Now after two years and only having mid-600 scores, I'm trying to fix the inaccuracies and this happened.
Never dispute accurate info. The creditor may have found some things that wasnt there before and updated your entry and there went the points. Theres no chance that past negs will be wiped out disputing stuff thats legit. Disputes are for inaccurate info on your reports only.
@Anonymous wrote:What's done is done. If it was accurate I'm not sure what dispute reason the rep would have put in. The CRA's report the dispute to the OC.Then the OC responds back. The CRA's dont make the decisions. They report what the OC enters in the investigation. Amex does not like frivolous disputes (disputing accurate information). They will respond every single time.
What happens in this case is FICO thinks its a new negative that appeared on your report. True. What was reported to them has changes and that updates what was missing before. Getting it fixed now is going to be a lot harder. Personally I feel like now you have to commit to getting it fixed. It went from being a few years old to fresh negative. There is no downside now in trying to get it fixed. You are already taking the hit. Yes, you made a mistake by disputing it but that is not a reason you should have to wear a "double negative". You dont want to punch anymore buttons and then be cut off from filing any more disputes.
Pull your paper report. You mentioned you have Experian. Experian gives you the option to print report. This printed report will have more detail than the curated web version. Go over the account. Look for any information that should not be there. If the debt was included in bankruptcy it should not have any updated information in the payment history. (the section that gives a status for every month). This is the section that usually gets updated when you dispute and old account, that makes it look like a fresh negative item. Also the "balance updated" status field will get updated to make it look like a new negative.
You want to this by mail. Print everything. If you have your old reports circle the correct information and the new incorrect information. Write a letter explaining that your report is "factually incorrect". If you need tips on what to say Google "factual disputes".
Disputing online and especially over the phone is blunt instrument. Not meant for precise issues.
Repeated disputes with CRA's will be listed as frivolous disputes and then they will cut you off from filing anymore disputes at all. Whats done is done. Lesson learned by the OP. Sending in info will result in another dispute. Its not going do any good. It is what it is. As we say here. Dont poke the bear.