Creating/automating custom receipts

I'm trying to automate customization of each receipt our customers receive upon purchase. To be more specific, I am selling physical merchandise for a video game online through Squarespace. In each digital receipt, I'd like to include a unique code the customer can enter in the digital game. So for every purchase, I'd like the receipt to include a unique code. I've contacted Squarespace support and I was told the only way to achieve this in Squarespace currently is to manually email each code to customers after each purchase, which would be too large a task for our small team given the high number of orders we receive. They also recommended I contact Zapier,  which I did, but they said it's impossible given Squarespace's current API. Both support teams were very helpful and even submitted feature requests to the dev team on my behalf! No complaints there, but I'm wondering if anyone on the forums has a possible workaround? I appreciate any ideas. Thanks! 

Hello Ocha! I have been trying to figure this out too for my business. I wanted to know if you had found a solution to this problem? I know that this post is old, but I hope that you will reply. Thanks!