Chase sent back the coupon stating they could not accept it because it contained a conditional notation. I sent it back removing the sentence , "however if the law has changed please accept this silver coin attached as payment."
They sent a letter back WITHOUT the coupon stating my agreement states payments must be made in U.S. dollars with drawn from a U.S. bank. Also stated the United States is NOT responsible for my debt. Lies! meanwhile am I obligated under contract to pay since the coupon is not drawn from a U.S. Bank?

UNITED STATES is foreign, so are you, if they don't send it back it's gone through, they aren't going to give up getting paid twice easily. Conditional acceptance, and they accepted it the second you mailed it. The postal rule.