Hi Vikii,
Since the short trade was not squared off/closed, you will have to deliver stocks (lot size * 1400) on Monday (T+1 settlement).
You can buy the stocks from the open market on Monday, but since the settlement is T+1 for stocks purchased on Monday, which means stocks purchased on Monday will hit your demat account only on Tuesday. So you will not be able to deliver stocks on Monday for the delivery and have short delivered. In this case the exchange will call for auction and settle the trade.
And if the exchange is not able to obtain shares in the auction market, then cash settlement happens at close out price, which can be 20% higher than the closing price on auction day.