Compensable hours of work

Dear PAO,

I filed a labor complaint against my employer. In one occasion, I was already at work when I recalled that there was a hearing of my case, which was scheduled on that day. I immediately asked the permission of my supervisor to leave the company premises to attend the hearing. Surprisingly, the company is now charging the hours used in attending the hearing to my vacation leave. Since the case was filed against my employer because of its fault, is it correct also that I should be compensated during the time that I attended the hearing?