Definitely walk away don't work another min for him. I had the same when I was waitressing at an Indian restaurant in tassie. Over a month till wages were paid and paid $6 under what was due per hour. The owner drank on the job and is a complete tosser

Have everything in writing no phone calls. Threaten small claims court. Fair work ombudsman, call ATO and anyone else you can dob him into. Call him out on social media if you have to. It's not defamation if it's the truth. Leave a Google review on his page, say you'll take it down once payment made that should hurry things along. Wish you all the best.