Ask the restaurant/store if they accepted your order already.

If they accepted your order already and if they can prepare it there is no need for you to do anything. Just wait for your order. If they can not prepare your order please reach out to the rider support team via Freshchat.

If they did not accept your order yet you can wait for a couple of minutes. Your order will be automatically canceled.
Only if your order was not cancelled after 15 minutes send a message to the rider support team via Freshchat.