Sorry guys, looks like they've already patched the site and going to apply the voucher again says "not valid for this product" for gift cards -> nevertheless you could still purchase $70 of goods with the same process with free shipping for the same amount.
Looking to maximise the use of the AMEX Cotton On deal here
-> Spend $50+ and receive $20 cash back, up to 2 times
Found that you can signup to their mailing list for extra 20% off purchase. Link at the bottom of the Cotton On webpage for signup
Used a temp email address and then checkout as a guest -> email coupon codes not linked to email address
Purchased 1x $20 and 1 x $50 gift cards totalling $56 ($70 - 20%) and then received AMEX cash back $20 => total price $36 for $70 value
Can repeat for continued savings at 49% depending on how many AMEX cards you have, 2 statement credits allowed per card
Also possible to use CashRewards 10.5% discount for further savings
AMEX deal has unfortunately been exhausted but details below
Save offer to your eligible Card and spend $50 or more, in one or more transactions, online or in-store at participating Cotton On Group brands by 31/12/2017 to receive a $20 credit, up to 2 times. Limited to 40,000 Cards to save offer. Exclusions apply.
OFFER TERMS
Valid at the following Cotton On Group brands: Cotton On; Cotton On Kids; Cotton On Body; Typo; Rubi.
Purchases made at Factorie & Supre are not eligible.
Cotton On Group locations can be viewed here.
Offer is limited to two credits per registered Card. Only spend on the Card number you register counts towards the Offer.
Excludes transactions where you do not spend directly in-store at participating Cotton On Group brands or online at the above listed participating websites, for example purchases made through a third party establishment or third party payment processor.
Offer valid at Australian locations and website only.
Credit is not redeemable for cash or other payment form.
Credit should appear on your billing statement within 5 business days from qualifying spend but may take up to 90 days from the offer end date.
Credit will not be applied to your Card account if your Card has been suspended or cancelled.
Credit may be reversed if your qualifying purchase is refunded or cancelled.
Full Offer Terms available here.
That's 48.6% off, not 51% off?