They tell you that you need to certify your school certificate in Polish embassy. If you study in Vietnam, then you must do it in Polish embassy in Vietnam. If you study in Indonesia, then in Polish embassy in Indonesia. Usually such certification is done by a country's ministry of foreign affairs, but neither Indonesia nor Vietnam is member of the Apostille Convention.
Now, I'm waiting the feedback from them on this case. But, still hope to be there Poland.
Call them not to wait.