the prob is u got no choice now. u r left with 2 options
1) pay what u 2 had agreed on and move in
2) pay him additional 5k

since u r afraid of option 1, u r left with option 2 only

im taking the assumption that he has shady background since u r so afraid of him

he can easily do something to u if he want. he is contractor. he got a lot of indon workers. he can immediately terminate one of the indon worker contract and him to disturb u before going back to his country. rm1k is enough to entice them to do that

assuming the task is less than 5k again

tell him to finish it off before talking about $$. if he dun wan, end his contract and get another