Show cause notice by officer in charge and improper charge trial

Sir, I have been issued with show cause notice by officer in charge of my section, though, officer in charge is not a competent authority.But , I refused to reply the show cause notice as officer in charge has threatened me to throw me out from service whether you give reply or not. Considering this as a serious charge , station commander awarded me reprimand (black ink entry) even he has not given me option to accept or not to accept the charge.Is there any chance to get fair trial and expungement of awarded punishment. As my officer in charge used to threaten and ill treat the subordinate