Disputing the debt doesn't restart the clock unless you admit that the debt is yours. You can get a validation letter in an effort to dispute the debt to prove that the debt is either not yours or is time-barred.

What happens if you dispute a collection?

Once you dispute the debt, the debt collector must stop all debt collection activities until it sends you verification of the debt. You can also use the sample dispute letter to discover the name and address of the original creditor. As with all dispute letters, you should keep a copy of the letter for your records.

Can a collection agency keep changing the date last updated?

The short answer is yes, a collection agency can continue to update the account on your credit reports. When you dispute an item, the Date of Last Activity (DOLA) can be updated. The date of last activity can change anytime there is new activity on your account. That could be a credit dispute or a payment.