First of all what you are asking for is legal advice. That is the work of A lawyer or a counsel.
Second of all what makes you think that you can make a demand for lawful money retroactively?
If someone took food off of your table would you be happy? So now in exchange for your ignorance you plan on taking food also off the table of someone who relied upon your nonperformance? If you want equity you must do equity!
I really do not understand your post. I will give you a template. Will you trust me that it will work for you? Friend that is part of the lesson plan around here. You must learn to take full liability for yourself. And clearly if you are asking someone else to provide for you a template you have yet to come to that point. If you truly understood then it would be a simple thing for you to write your own letter. Therefore why do you want to take food from another man's table?
Shalom,
MJ