Additional information concerning contracts:
In Indonesia, all contracts MUST be in Indonesian. That is not to say that they cannot contain translations to other languages, but the contract is completely worthless if it is not written in the Indonesian language. If your contract is NOT written in Bahasa Indonesia, it is toilet paper, all the meterai (tax stamps) and signatures notwithstanding.
Next, all contracts MUST have the five essential parts to be valid: definitions, jurisdiction, performance, warranty, and remedy. In other words, they must clearly define the parties and any special terms. They must state what legal authority controls the contract. They must state clearly what is expected of all the parties to the contract. The parties must warrant their intent to perform in good faith. They must state any penalties if performance is not met, and they must state what the parties must do to seek relief (trial, mediation, arbitration, etc.).
Finally, each party must receive an original copy of the contract with a meterai (tax stamp) under the signatures of all counter-parties. Demand a copy of the contract and walk away if it is not forthcoming.
One additional note, things like bonuses required by law do not need to be included in the contract to be binding on the employer. The employee may waive those legal rights if it is specifically spelled out in the contract (usu. things like Jamsostek).
Also, if your contract does not have an English translation, you may demand that one be provided to you from a certified translator. The certified translation will have a notary stamp on it. Unless you speak and read fluent Bahasa Indonesia, do not trust anyone to read it to you or bang out a ‘translation’ that is uncertified. You may be surprised at what you have signed to if you don’t get a notarized translation.
The most important thing to note here is that if your contract in NOT IN INDONESIAN, then you DO NOT have a contract.