If you created a gift card when you made a donation (see how-to here), a PDF of the card will be saved to your MyGiving account. If you need to resend this to the gift recipient, you can. Just download the PDF from MyGiving and email it directly to the intended recipient.
Donation gift cards you have created can be downloaded from MyGiving by logging in to www.givenow.com.au/login then going to Donations > View Donations > three dots / Gift Card.