sorry tumpang thread.
can anyone advice me?

my house reno progress is about 80% done but this situation had lasted for 2 weeks (actually has overdue), the contractor take his own sweet time and at the same time keep asking me for money. Then now he ask me again for money to pay for the aluminium glass door and window, ard 2.5K. I was thinking not to pay first because I intend to pay him one shot (final payment left 3k plus only) cuz he promise this weekend can end the work. But I afraid after I pay him, he will continue to drag the work again and if I dun pay him now, he will say then the job cannot complete on time. Please advice what should I do??