It is true that you worked there for two months. If your colleague's salary is the same as yours, you will be given a lot of promised salary at first. Of course, unless you breach the contract, you have the right to ask him to pay your due salary in full. If anything happens, you can report it to the local labor arbitration Committee, and they will mediate. If mediation fails, you can bring a civil lawsuit to the local court. The labor department can handle it completely! What you need to do now is as soon as possible. You can also think about the reaction of the media, and the effect is sometimes the best! I hope you get it soon!