I've ~$500 in cashback waiting to be paid, nothing further is being approved for payment and my last payment was in August 2018. They haven't responded to any queries I've made for the past few months.
Feedback is starting to build-up on their Facebook Page and Product Review
I would say DO NOT USE & probably worthy of an alert to other OzB members.
https://www.ozbargain.com.au/node/387253