How to extract donor form data immediately via API / integration?

Site URL: http://reteti.org/kapai

I'd like to send donors a Certificate of Appreciation immediately after they donated, so I'd need to pull all the data in the Donor Form which they fill out. 

However, I'm struggling to see how I can get the data automatically added to a spreadsheet. 

The API seems to only pull ORDER data.
No Donor Data. 😞

I can't manually download .csv files and then upload to the software that generates the certificates. We're expecting big volumes. 

Any one with any idea how to pull all the donor data automatically? 

Note: Although they appear in Squarespace as orders, the Orders API does not provide access to donations. Instead, donation information can be accessed using the Transactions API.

https://developers.squarespace.com/commerce-apis/orders-overview