Update to cart for shopify website

Need to update the cart section of the website. Either do this for the site: Option 1 When the user enters the postcode, if it is within the list, everything will function normally and they will checkout. However, if the entered postcode is not within the list, a message will pop up informing the customer that the order is partially processed and to complete the order, they have to get in touch with the business owner/merchant (with contact details, if any). (note: The system will download all postcodes to the backend for Melbourne Metropolitan area or the merchant (Tiles Republic) will have to enter all necessary postcodes in the backend for which the pricing is standard. ) Option 2: To show a pop-up message as soon as the user enters a postcode (regardless of whether the postcode lies within Melbourne Metropolitan or not) informing them something like the below-mentioned. To show this twice (product page and cart page) to ensure they don't miss out. Sample message: "Important notice: Delivery postcodes outside of Melbourne Metropolitan would incur additional shipping charges. If an order is placed with a postcode outside of Melbourne Metropolitan, the order will only be partially processed. The customer will have to contact the merchant to complete the order via mail or call with their Order Id."