From the upcoming Coles catalogue sale starting Wednesday February 23.
20x Flybuys Points with Apple Gift Card (Excluding $20 Cards, Limit 45,000 Points Per Account) @ Coles in-Store Only
$50 = 1,000 FB Points
$100 = 2,000 FB Points
$200 = 4,000 FB points
Any questions, check out the FAQs.
PS - Woolworths has 10% on some gift card.
I was just about to post a comment saying that the acceptance of the Vanilla Visa gift card is at the discretion of the staff member, because of the signature requirement at Coles and the terms you were told about by the staff member.
I'm sure there will be a different staff member at the self-service checkouts later today, but there's a good chance a lot of the staff at that store have been instructed by store management to reject people wanting to use Vanilla Visa gift cards as a payment method for gift cards.