If you need to get access to an invoice for a previous payment, perhaps because your payment receipt went to junk, or you have misplaced it, you can always access an invoice via your Enudge account.
To find your payment history and invoices:
Click on your name in the top right hand corner, and choose 'My Subscription'
Scroll down to the bottom of the screen and click on the 'View Payment History' button.
From the list of payments, which are shown in reverse chronological order, you can click on the invoice number (right hand column) to view the tax invoice.