You can download a copy of the receipt for your payment to Parsec via visiting the original purchase receipt sent to the inbox of the account that made the payment (in the case of Parsec Teams, the Team owner).
The receipt will be sent from sender receipts@parsecgaming.com - this mailbox is not monitored so please do not send inquiries to it.
At the bottom of the email, there will be a link called "Download as PDF" which will send you to a link to a PDF version of the receipt.