Unfair treatment

It's Mr John Phonoshe I don't know if u can assist me I'm currently employed by Gauteng GDE at Sedibeng West District last year I found out that I was being under paid I did put a dispute with my HR in June 2018 they said they are also aware of the problem, I completed all the documents but up until date I never received response, please assist, I was also on employed temporary by the same department from April 2014,on 15March 2019 I app**** for compasation due to me cause I was temporary until date again there is no response I contacted GEPF cause one of my colleagues received her money from them and I was told that my file is in their archives please help