Mo. Rev. Stat. § 290.110
Whenever any person, firm or corporation doing business in this state shall discharge, with or without cause, or refuse to further employ any servant or employee thereof, the unpaid wages of the servant or employee then earned at the contract rate, without abatement or deduction, shall be and become due and payable on the day of the discharge or refusal to longer employ and the servant or employee may request in writing of his foreman or the keeper of his time to have the money due him, or a valid check therefor, sent to any station or office where a regular agent is kept; and if the money or a valid check therefor, does not reach the station or office within seven days from the date it is so requested, then as a penalty for such nonpayment the wages of the servant or employee shall continue from the date of the discharge or refusal to further employ, at the same rate until paid; provided, such wages shall not continue more than sixty days. This section shall not apply in the case of an employee whose remuneration for work is based primarily on commissions and whose duties include collection of accounts, care of a stock or merchandise and similar activities and where an audit is necessary or customary in order to determine the net amount due.
§ 290.110, RSMo