If you purchased the product on the Google Play version, you can check your order number in the following way
▼Order Number Confirmation Procedure
An email with the subject line "(Order: Date) to Google Play" will be sent to the Google account (Gmail) where the purchase was made.
Please include your order number in the text.
※The order number is in the form GPA.0000-0000-0000-00000.
※If you cannot find the email, please follow the instructions below to check your order information.
||Sign in to your Google Wallet account (http://wallet.google.com/manage).
||Select "Transactions" on the left side.
||Please select the transaction to be covered and enter the "transaction id" that appears on the right side of the screen.