You write:
Registering is quick and easy:
Pay by Credit Card, PayPal or Bitcoin securely (...)
Registration is delivered by email containing a download link,
All programs have a full trial, before purchasing check the program functions as required, refunds cannot be given after registered program is downloaded.

So, the correct sequence is this: I buy the trial version, try it for 21 days and at the end I receive a link to download the full version. If I want to have the full version i simply download it (and disinstall the trial) otherwise I ask for a refund of what I paid for the trial version.
Just to be sure, thanks.