Myer seems to have M.A.C products at 20% off today.
M.A.C. recently dropped their lipstick prices from $36 to $30, and with 20% off comes to $24 before cashback.
Shopback's has 20% cashback from Myer until 4pm.
The shopback page states this exclusion under the cashback button:
Cashback not applicable for Products from brands such as: CHANEL, Dior, Tom Ford, Jo Malone, YSL, Review
but doesn't mention M.A.C.
And yet as pointed out by povertytrap, under 'Other Terms & Conditions' at the bottom of the page:
> Cashback not applicable for Products from brands such as: CHANEL, Dior, MAC, Jo Malone, YSL, Review
So no idea if cashback will apply or not.
Update 3:40pm: According to shopback, the terms at the bottom of the page are out of date. M.A.C. is elligible for cashback.
Update 4:00pm: Shopback cashback is now 9% which is still an upsized cashback in case you missed out on 20%.
Good deal but further down on the ShopBack t&cs it says Mac is excluded from cashback.