Whenever any employer has entered into a collective bargaining agreement with a labor organization or association of employees providing for payments to a health or welfare fund or pension fund, or other plan for the benefit of employees, it shall be unlawful for the employer to fail to make the payments required by the terms of the agreement. Further, any employer who willfully fails to make payments within sixty (60) days after they become due and payable shall be guilty of a misdemeanor and upon conviction shall be fined not less than one hundred dollars ($100) nor more than five hundred dollars ($500) for each offense, and/or imprisoned not exceeding one year for each offense.