Several factors come to mind.....
First, if the creditor no longer owns the debt (i.e., the debt collector purchased the debt), then you can no longer pay the creditor, period.
Any payment would have to go to the debt collector only.
Second, even if the creditor still owns the debt (i.e., the debt collector only has assigned collection authority), some assignment agreements require any and all payments must be made thru the debt collector. Before sending any payment to the creditor, you should give them a call and inquire as to whether they will even accept payment.
That might be a good time to also ask whether you should send any payment to a special address, such as their internal collection department.
Third, if part of your goal is to also obtain deletion of the reported collection, simply sending payment to the creditor will not lead to any required deletion.
You can either send a pay for deletion offer to the debt collector, requesting their agreement to delete their reporting in exchange for payment.
It is also possible to get the collection removed by first getting the creditor to terminate their assignment to the debt collector, but that approach requires voluntary termination prior to any payment to the creditor, and then requires the debt collector to therafter report deletion. It is often fraught with problems.
