It shall be unlawful for any rural policeman in this State to accept or receive any fee or reward for making any collection of any debt, foreclosing any chattel mortgage, bill of sale or other lien or compromising criminal cases. Any rural policeman within this State who shall violate the provisions of this section shall be subject to a fine of not less than twenty-five dollars nor more than one hundred dollars or imprisonment for a period of not less than twenty days nor more than thirty days and shall have his commission revoked by the officer issuing it. But nothing herein shall prohibit any rural policeman from collecting delinquent taxes.