So, I had one baddie removed from all of my reports a couple of months ago. However, to my surprise, this morning the debt was sold to another agency and BAM... my score tanked 35 points! 
So, here goes another two months of disputing and waiting for it to come off again. I understand collection agencies are allowed to resell debt over and over, but I really wish it could be stopped from being resold after a legitimate dispute has been resolved.
@Kreewrote:What was the legitimate dispute?
I went through the dispute resolution process with Experian and Transunion of what was a mistake on my CR.
What was disputed/how it was disputed could change what advice you are given.
I recieved a resolution letter from both Experian and Transunion of the dispute results which was the entry that was being disputed was delted from my CR.
I believe that answers what you were asking.
@Kreewrote:
@avp99wrote:
@Kreewrote:What was the legitimate dispute?
I went through the dispute resolution process with Experian and Transunion of what was a mistake on my CR.
What was disputed/how it was disputed could change what advice you are given.
I recieved a resolution letter from both Experian and Transunion of the dispute results which was the entry that was being disputed was delted from my CR.
I believe that answers what you were asking.
Unfortunately not quite. Why did you dispute? Was it a balance amount, a date, the wrong name? Why did you say "This is not a valid debt."?
Disputed because the debt was not mine
As an additional question, what did the resolution letter say? Was it deleted because your dispute was recognized by the CA or because the CA never responded?
Resolution letters said : "Outcome: Deleted - This item was removed from your credit report". It does not indicate if it was recognized or never responded by the CA.
@Anonymouswrote:
I have similar thread. If the Original creditor debt was in your report seven years the new collections agency cannot report the debt. Hoping others verify this
@Ginerbrew, I had the erronious information removed from my CR with the help of a firm I hired (not sure I am allowed to publish their name on here). In other words, they wrote the dispute letters on my behalf. the erronious information was legitimatly removed (deleted) as part of the dispute process and confirmed by Experian and Transunion. However, I was told the CA sold this "file" to a different CA and the new CA has reported this information that was legitimatly removed through the dispute process. I am told that in my case, it is rare that information that was deleted from the CR should show up again. However Collection agencies are allowed to sell "debt" to other companies even if it was deleted. It sounds like you might be in a slightly different situation. I hope that helps.
@Anonymouswrote:
Even if the CA sells the debt they cannot report it if that debt is 7 years or older.
good to know, I am going through with the process of disputing again and I have also filed a complaint with the CFPB. I hope you can get yours resolved.