The Date of Last Activity is when one of three things happens on any active account being reported: the consumer makes or misses a payment or the balance has increased. Some places want you to think that the Date of Last Activity will "start the clock" on the item all over, but contrary to popular belief, the Date of Last Activity has nothing to do with when an item will be deleted from the credit report.
The Credit Bureaus control the DLA
Because the credit bureaus control the activity on ones report, it's just natural that they control the Date of Last Activity (DLA), and as an effect of this, some debt collectors have been know to make changes to an account to trigger an update within their company to be sent to the credit bureaus causing a new listing to be added to your report, the more recent a listing on your credit report, the more of an impact it may have, so you do not want a new negative listing being unfairly reported. This is why it is so important to monitor your credit!
Making Payments on past due accounts
Making Payments on past due accounts does not change the original delinquency date, it also will not "start the clock" all over again on a listing on your report. Now it's always a good idea to pay your debts, especially ones that are past due, but if you have negative listings on your credit report due to these debts, then you want to make sure the creditor/debtor will remove any negative listing they put on your report in return for payment. Don't let the creditor tell you they "can't" remove a negative listing. Well if they are referring to themselves, "they" are probably right, but don't let them lead you to believe that the company can't or that it is impossible for it to be removed, because that would be 100% incorrect.