I see several issues floating about that seem unanswered. Here is how I view your situation.
First, I am not sure that ATT is "out of the picture." I dont see that they have said that they sold the debt to a CA, just that they referred it. So ATT may still own the debt.
The fact that CA1 did not accept your payment because their collection was terminated is a pretty strong indication that ATT still owns the debt, and moved their collection agent over to CA2, Just my speculation, from the facts. If ATT still owns the debt, it is possible to offer payment to either ATT or CA2.
Did ATT ever report the lates on their OC account to the CRA? The reporting of the 30-day late by the OC is unrelated to the collection postings.
If the CO still owns the debt, your PFD offer to them would relate only to the delection of any 30+ lates they may have reported. The OC cannot agree to or force deletion of any credit reporting done by a CA. So PFD to the OC wont remove any CA reporting.
If you choose to make a PFD offer to a CA, the first question is, which CA is currently posting to your CR? You only PFD to one who has both posted to your CR, and has authority to collect the debt.
If CA1 is still in your CR, but tells you that they are no longer authorized to collect the debt, then you cant PFD them You can only GW them.
If CA2 is now authorized to collect, but has not posted to your CR. then CA1 can remain in your CR until CA2 posts. Once CA2 posts, then CA1 must delete.
In that situation, until CA2 posts, you cant PFD either CA1 of CA2. CA1 cant accept payment, and CA2 has no posting to request deletion of.
If CA2 then posts to your CR, that is when you can PFD them. If they accept, the only have authority to delete the CA posting, and not the prior 30-day+ lates posted by the OC. You would then have to go back to the OC and separately request their GW deletion of that derog, or derogs.
On the issue of whether and when to pay, I wont offer advice, because that is a choice that only you can make. PFDs offters are just conditional offers. If they dont accept, and no one can predict whether or not they will accept, or even respond, the debt remains unpaid. They can always then take legal action. So waiting for a hopeful PFD acceptance is not without peril. In your case, since the debt is low, and apparently lots of time still remains on your probable SOL, I dont see the threat of legal action as imminent. Your risk, and thus your choice. I dont think it is sound advice to just, in all cases, summarily recommend just sending out a PFD offer, and waiting for response.
I agree with other commentors. Marking as PIF does not help credit score. It does help upon a manual review of your credit report to show that a prior debt was paid, so it is not without benefit to you, but it wont reflect in your credit score. If they tell you it will benefit your score,they are either lying or dont understand credit scoring.
