If you setup your Wix ecommerce website with a shopping cart before mid-2015, you likely created your site using the older Wix editor. And if you use Authorize.net for your payment processor in your old store, you should note that your customers may no longer receive the receipt emails from Authorize.net.
This is caused by some security changes on Authorize.net's end. Wix is currently (as of Feb 10, 2016) advising their shopping cart customers to upgrade their websites to the new shopping cart called WixStores. In fall of 2015, Wix released a new editor with lots of improvements, including a new WixStores ecommerce cart. Apparently, WixStores is an entirely Wix-built system, whereas their previous shopping cart was a collaboration with third-parties and had limitations and issues, including the security issue that caused Authorize.net to no longer function well with the old Wix shopping cart, resulting in the loss of email receipts. While the cart will STILL process the credit cards through Authorize.net, the customer will never receive an email receipt of the order. A problem for sure!
But to upgrade an old Wix store to the new WixStores platform, there is no easy conversion over. You have to delete your old shopping cart/store entirely, and then install the new WixStores shopping cart, resorting in the loss of all the products setup in the old cart. This is FAR from ideal.
I called Wix and the best advice they are offering, if you want to continue to use Authorize.net, is to have customers duplicate the website, delete our the old shopping cart in the duplicated site, and then add the new WixStores Shopping Cart to your duplicated site. The next step: you have to re-add all your products to the new WixStores system, and re-setup your Authorize.net API and transaction keys and settings. If you duplicate your website, you can open the old website editor and the new website editor in two windows side by side while you manually re-create all your products. The only fortunate thing is that your product photos will still be in the library.
This is a very poor solution for Wix to offer their current ecommerce customers, it's not ideal for lots of reasons to duplicate your website (SEO, URLs changing), and I can't believe there is not yet an import/export feature to go from the old shopping cart system to the new system.
Also, I was disappointed that Wix did not notify their old shopping cart customers that Authorize.net would cease to send receipt emails, so it wasn't until a client notified me of the issue that we discovered and were able to deal with the problem. The solution? We had to duplicate the website, and then add the new WixStore and re-create all the products, which was a four-hour process. Luckily, we only had to setup 6 products and a few categories, I can't imagine having to do this with a Wix store with 100s of products!
Wix phone support did say that they believe the development team is working on a solution for an easy upgrade to the new system, and I've also prodded them to ask for import/export features as well, which is a huge lacking feature of both the new and old ecommerce carts. While I think Wix is a great website editor / builder, I think they still have a long way to go in the ecommerce department. Hopefully their ecommerce will improve over time, for now, I will recommend that clients with sophisticated ecommerce needs use a better ecommerce platform such as Shopify, until Wix has improved their system.
Here are some screenshots of the new WixStores checkout process - it does appear there is a receipt page with limited details of the order including price and customer address - you cannot customize this page yet, but that too, Wix is apparently working on: