SHoggard wroteI'd question the legality of taking and witholding an employee's personal documents - school certificate, IC, passport, whatever - sounds too much like 'slavery' - plenty of Indon maids overseas have their passport 'retained' by employer or maid-agency this opens them to abuse from which they can't escape. Since you are in Indonesia, she probably didn't have a passport, so school certificate probably serves a similar function - to prevent he getting another job.
I'm sure your intentions were not this... but consider the story she probably told the Banjar to get them so hot n bothered.
Change your 'HR' methods
Witholding employee's personal documents is normal in indonesia. Not just in Bali, many companies in the capital (Jakarta) keep the personal documents that belong to their staffs, especially if the job is dealing with money.
Before the staff is hired, the company would ask him/her to sign a contract agreement that mentions staff's approval of surrendering the personal documents.
In this case, if boogeywoman have that signed agreement, she has strong position to deny the threat.