This happened to me. I called the ORIGINAL creditor. They, fortunately, still had the records and I was able to get it cleared up with them. They then contacted the debt collector and had them remove the account completely from my credit report.

NO they cannot IF you requested validation within the first 30 days after receiving their first communication - they cannot legally place it on your credit report until they validate the debt.
Placing it on your credit reports IS a collection activity

It is a violation and actionable for up to $1000, if you wish to pursue it.
§ 813. Civil liability [15 USC 1692k] (FDCPA)

They had violated at the least:
FDCPA
§ 809. Validation of debts [15 USC 1692g]
(b) If the consumer notifies the debt collector in writing within the thirty-day period described in subsection (a) that the debt, or any portion thereof, is disputed, or that the consumer requests the name and address of the original creditor, the debt collector shall cease collection of the debt, or any disputed portion thereof, until the debt collector obtains verification of the debt or any copy of a judgment, or the name and address of the original creditor, and a copy of such verification or judgment, or name and address of the original creditor, is mailed to the consumer by the debt collector.

You might click on my profile and do some reading in the links I have listed - the FDCPA, FCRA, etc.

Yes, they can add this to your report. They must validate the debt if requested.

This is wrong! “Debt collectors collect money. They don’t adjudicate disputed accounts . you must go through the store or agency that reported that debt. Y ou can send a certified leter to the credit bureau explaining the problem . but only the store can take it off your file.”

Debt collectors do collect money, but if requested they must validate the debt. Which means they must give you complete accounting of the debt including original amount due, any payments you have made, interest charged, penalties, fees, etc. This must all add up to the amount that they are suing for or attempting to collect on. If you are disputing the account as an invalid account, they must attempt to provide some proof that it is in fact your account.

Also, the debt collector has the right and ability to remove the negative information from your credit report.

I would send another letter with copies of the last letters and cards from certified return receipt mail and tell them that they have to validate the debt or you will file suit for negligence, damage to your credit report and violation of the Fair Credit Reporting Act and violation of the Fair Debt Collection Practices Act

Yes a debt collector can report on your Credit Report. You have done everything reccomended as far as trying to contact the agency and sending a certified letter. One other thing you can do is dispute the debt with the credit reporting agency. Here are their websites where you can get more info.

if the websites don’s show up clearly just google “experian dispute” “Equifax Dispute” and “Transunion dispute”

Debt collectors collect money. They don’t adjudicate disputed accounts . you must go through the store or agency that reported that debt. Y ou can send a certified leter to the credit bureau explaining the problem . but only the store can take it off your file.

Absolutely. They can ding your credit at anytime. Your only recourse is a law suit if they did it and were incorrect in doing so.

Yes, a debt collector can report you to the credit bureau. You need to notify them and dispute it unless you do owe the debt. It takes a long time to straighten up your credit after it appears on your credit report. Be sure you have all the information before contacting them.