If purchases were made via the Apple App Store, you can find your purchase history by going to the official Apple Support site
Go through the site and you will be able to find your Purchase History.
 
If purchases were made via Google Play, you can find your purchase history by going to the official Google Support site.
Log into your Google account used to make purchases, go through the site, and you will be able to find your Purchase History and Activity.
 
If you have tried the troubleshooting tips above and are still having difficulty locating a past purchase, please reach out to Customer Support here or send an email to MTGPQSupport@d3go.com and we will be happy to assist you.