I must say that I am rather taken aback by many of the previous posters comments implying it's all your fault, you shoulda known better, and shoulda just paid your bills ontime. Allow me to toss in a bit of hope.
Once you've disputed, and the CRA validates, you do have another option. CRAs are required by law to provide you, upon request, with the method of verification used.
FCRA section 611(a)(6)
(A) In general. A consumer reporting agency shall provide written notice to a consumer of the results of a reinvestigation under this subsection not later than 5 business days after the completion of the reinvestigation, by mail or, if authorized by the consumer for that purpose, by other means available to the agency.
(B) Contents. As part of, or in addition to, the notice under subparagraph (A), a consumer reporting agency shall provide to a consumer in writing before the expiration of the 5-day period referred to in subparagraph (A)
(i) a statement that the reinvestigation is completed;
(ii) a consumer report that is based upon the consumer's file as that file is revised as a result of the reinvestigation;
(iii) a notice that, if requested by the consumer, a description of the procedure used to determine the accuracy and completeness of the information shall be provided to the consumer by the agency, including the business name and address of any furnisher of information contacted in connection with such information and the telephone number of such furnisher, if reasonably available;
(iv) a notice that the consumer has the right to add a statement to the consumer's file disputing the accuracy or completeness of the information; and
(v) a notice that the consumer has the right to request under subsection (d) that the consumer reporting agency furnish notifications under that subsection.
FCRA section 611(a)(7)
Description of reinvestigation procedure. A consumer reporting agency shall provide to a consumer a description referred to in paragraph (6)(B)(iii) by not later than 15 days after receiving a request from the consumer for that description.
1. With the CRA's investigation result in which they validated the account, call the CRA at their toll-free number.
2. Give them their reference number and ask for their method of verification. If they act dumb, tell them the method of verification they are required to provide per FCRA section 611(a)(7).
3. They probably never called the original creditor (OC) and relied upon a third party or inhouse database to verify. They may or may not admit it. They'll probably cough up the OC's phone number. Probably will be a general number.
4. Call OC and inquire of their records. Remind them of their letter stating it went to collections in error.
5. When they reconfirm that it was reported to collections in error, express thanks to the person for all their help. Get the person's name and direct line or extension number.
6. Call the CRA and tell them the OC confirmed it was reported to collections in error. Tell the CRA they need to open another dispute. The new information for the dispute is the name and number of the person with whom you spoke at the OC. Get a confirmation number for the new investigation.
7. If they refuse, tell them you will sue for willful non-compliance under FCRA section 616.
8. If they still refuse to open a dispute, ask for the person's name, a direct number, and their employee ID number. Then send your dispute via CMRRR (certified mail returned receipt requested) again. Note your calls to the CRA and OC in an effort to obtain their method of verification. Repeat in your letter that you will sue for willful non-compliance if they fail to open an investigation. Include a photocopy of the letter you received from the OC, and the name and number of the person at the OC with whom you spoke.
Document your phone calls on a sheet of paper. Note the date, time, phone number you called, person you spoke with, and summarize the conversation.
If you don't get a delete, time to take everything you have to a lawyer. Here are two sources of lawyers experienced in this area.