How can I change the message if the zip code does not exist or match?
I want to change from the current default message " Product cannot be delivered at your pincode location" to "Currently, we are not delivering to this Zipcode. Please check later "
Assuming you are talking about your purchased items. Please check the item documentation hopefully you will get necessary support. If you have still problem with the theme then The best way to get the support is Contact your purchased item Author. Contact Author and let them know. Author will be very happy to assist you.