The lender CANNOT REFUSE a payment in dollars, in the USA. There is a legal maxim, "To tender is to pay".

In simple terms, if I owe you $100, and I go to your office, or we meet at a third party site, and I place a $100 bill on the table before you, YOU CANNOT LEGALLY REFUSE the payment. If you walk away, YOU HAVE BEEN PAID, even if you ignore the $100 bill. My debt has been canceled, and I owe you NOTHING, even though you reject the money. I can pick up the $100 note, and take it home, and (assuming I can give evidence of my tender of the money) write off the debt. Any court in the USA will uphold the payment.

Legal tender is a form of money that a government officially recognizes as a valid way to pay off debts, taxes, and other financial obligations. While a business is generally not required to accept legal tender for a purchase at the point of sale, creditors must accept it for the payment of a debt. In the U.S., this includes coins and paper currency like Federal Reserve notes.

The phrase "legal tender for all debts, public and private" means that U.S. coins and currency must be accepted as payment for all monetary debts in the United States.

Shit "currency" like bitcoin has NO SUCH POWER of debt cancellation.