The manpower regulations of Indonesia are written to heavily favor the employee over the employer. This is great news for any Indonesian but counts for very little if you are non-Indonesian.
You may well find yourself in a situation where you have the law on your side and absolute proof that your employer has broken an agreed contract of employment. However the reality is, it doesn't matter who is right and who is wrong, you will find it very difficult to have any legal success without being Indonesian. While it may not sound like a fair system, that is the reality.
If you would like to read the Indonesian manpower regulations you can download a copy from here. Don't take it too literally.