Sometimes, when there are situations where an end-user is asked to provide his/her purchase receipt, so that a purchase issue can be investigated.
Finding your Receipt
When purchasing the content, Google sends a receipt to the e-mail address used to make the purchase. It might take a few days for the receipt to arrive.
If you did not receive it, or are unable to locate it, you can find it in your google account:
Please note that the above relates to a product of a 3rd party, not being Applicaster. It is thus subject to change at any given time, according to the sole discretion of Google.
For further details on Google Store charges and receipts, please turn to the official documentation of Google on the matter: