I found this website article about financial matters whilst searching Google for some info. There is a lot of cases mentioned so it may help, even though I don't see Missouri these cases tend to refer to other cases and there may be a Missouri case for you.

From: "http://melochi.org/five-dollar-coin"
Hopefully that'll help you. More:
"http://legal-dictionary.thefreedictionary.com/Account+stated"