If the coupon you used was a one time use coupon, you will not be able to use it again, however if it is a multi use coupon, you can use it as many times as you want.
Unfortunately this is not possible as the order processing happens as soon as you place an order. However you can cancel the order as long as it has not been picked up by delivery executive and place a new order with the correct size.
You can check the status of your order in the My Orders section. Gofynd constantly update the status of your order and notify you via the app, email or SMS in case of late deliveries. If you haven’t received any communication from Gofynd regarding a late order for more than 48 …