Sec. 20. An action to:
(1) contest the validity of the adoption of a plan to declare that the plan has not been validly adopted; or
(2) enjoin the operation of a plan;
may not be instituted with respect to the adoption of the plan under section 19(a)(1) of this chapter at any time later than the one hundred twenty (120) days following the publication of the notice required by section 14 of this chapter or under section 19(a)(2) or 19(a)(3) of this chapter at any time later than the thirtieth day following the election at which the plan is adopted.