Looks like eBay didn't decide to go through with the discount.
No date and end time has been listed though, and there's a disclaimer in the T&Cs:
Use code:This offer is available for as long as it is advertised by eBay on www.ebay.com.au (“Offer Period”). eBay reserves the right to cancel the offer at any time.
PCYBER
A minimum spend of $75 per transaction applies. The total discount is capped at $300 per transaction. Limit 2 transactions per person during the Offer Period.
Multiple items may be purchased in one transaction (up to a maximum of 10 items per transaction).
T&Cs:
https://pages2.ebay.com.au/Buyer_coupons/pcyber