PT 1: Say a company was sued by a bank for not paying back a loan, and the company proceeded to pay off the loan by court order. If a year later, a debt collector contacted the company and demanded the full amount of the loan because they were a Holder in Due Course, would they be entitled to this payoff? Even if the company already paid off the debt to the bank due to a court order?

PT 2: NOW consider these facts: After the company paid off the loan, say the bank wrote a nice letter saying "thank you, your loan is discharged and you do not owe us anything else." A year later, the debt collector contacted the company and demanded the full amount because they were a Holder in Due Course. Would the Company be able to raise defense that the note was discharged??

If not, how could they have avoided this and had full proof that the note was in fact discharged?