Add Zip Code validation to Checkout in Wordpress WooCommerce

I’ve got an e Store (Woocommerce) where I need an extra validation to the Zip code field in checkout phase. I have two delivery methods. Pickup and Free Delivery. When the customer chooses Free Delivery the Zip Code field should validate if the typed Zip Code in the Zip code field exists in the database (our just a simple php/txt file). When the Zip Code does not exist an error message should appear (the same way as when no zip code has been entered). The message should be: “Sorry, but we do not deliver in your area” (see attached screenshot) When in the file the Zip Code 1238 is noted (so I deliver my products to that Zip Code), and the user is from 1238AB then nothing should be stated. (this is almost the same as with the shipping calculator -> local delivery, but in my opinion the shipping calculator is an extra unnecessary move for the user) Other demands: I should be able to add/edit numbers to the list. When users enter “wrong” zip codes it should be logged into another file. I want to be able to add the piece of code into the [login to view URL] of my child theme Extra info: In the Netherlands the Zip Code looks something like 1234AA. The first four numbers are from the city, the last two letters are from the street. In the database/file a list of all the cities (so the four numbers) where I deliver products is created. So the letters are not of interest in the validation. If you have other easier/better solutions for this, please tell me.