Ms Cornelius told the Authority that Mr Singh reacted in a "rude and belligerent manner" and failed to address the issues.
She then told him she felt she had no choice but to resign, in which he responded: "You'll have to do what you have to do."
She later resigned. It took her 10 weeks to find another job.
Ms Cornelius told the Authority she was unjustifiably dismissed.
The Authority found that HPG never addressed her concerns and in absence of any response or defence found Ms Cornelius was constructively dismissed.
The Authority said HPG seemed to have gone out of their way to "stall and impede the process" by not appearing before the Authority and refusing to provide wage and time records.
Payment of almost $12,000 was ordered to be made to Ms Cornelius by June 16.