If the original creditor accepts payoff, they should communicate that fact to their collection agency. But if in fact this is a junk debt buyer, it now owns the debt and thus the payoff would have to be through them.

If the registered lien holder is still the original creditor, it raises a possibility that you could negotiate a release of lien with the original creditor while leaving your obligation to the junk debt buyer unresolved. But if the junk debt buyer has any sense, they purchased the lien along with the contractual debt.