This has been confirmed working by myself and another ozbargainer (by pm) who also confirmed getting the $25 Gift card and a full refund of Amazon Prime ($99 USD) from this deal.
Amazon Prime is fully refundable as long as you do NOT use any features of Amazon Prime.
If you cancel at any other time, we will refund your full membership fee only if you and your account did not make any eligible purchases or take advantage of Prime benefits since your latest Prime membership charge
For the purpose of this promotion, i would recommend you create a new Amazon account & sign up to a paid Prime memebership via Topcashback link. Then sign out and wait for your $25 Gift Card. Then chat with amazon and cancel Prime and get your refund