Kogan Australia review: I purchased an IPhone pro max

I purchased an I phone pro max with credit card and my altitude rewards. The phone arrived Dead. Non responsive. Had to return it. They are refusing to issue a refund and are holding my altitude vouchers and cash. I have requested they return them to Westpac.
We are talking about $1800 and almost up to two thousand dollars.
This is to be returned Kogan or I will take you to Current Affairs and have a solicitor publically take legal action against you KOGAN ! Return all my money.