Record down everything, ask the BSC officer if its HDB regulation to rectify it that way.
If the officer not helping, email HDB.
If HDB not helping, email the minister in charge
If still no, then email the PMO. If still like that... think no chance le.. but get it black and white from PMO to say that they allow it to happen.
Remember to keep a black and white from them, saying that if they did not change the window and if the window were to drop off, it not your responsibility but HDB since they gave a defective window. Unless they have a written evaluation from a professional saying the window is safe for use.