I hold a promissory note from a small company. The note is due, and I verbally asked for the company to pay the note. They said they cannot afford to, but I know they absolutely can, without injury to the business, because I know the book keeper. What do I say in a letter to them that I want the note paid? Do I simply say that the note is due and I "demand" it's immediate payment, or are their more correct terms to use? Thank you.