Who may file a complaint?

Article272 Law No 8/2012 on Legislative Election

(1)   In the event of a dispute on thedetermination of election vote acquisition nationally, Election Contestants canpropose revocation of the determination of election vote acquisition by KPU tothe Constitutional Court.

http://aceproject.org/electoral-advice/archive/questions/replies/286046320/230159556/Unofficial-Translation-of-Law-8-2012-on.pdf