First of all, you ask the sales girl if there is any way. If she answers no, you can just say that the payment will be delayed for one month.
The developer will definitely make you pay a late fee or something. It is impossible to confiscate your savings. Now the state has repeatedly asked developers not to confiscate the customer's deposit. The only thing you have to do is to negotiate with them. How much is the penalty for one month? It is generally three ten thousandths of the remaining house price. Not much money.