Terrible service

I had someone to fit granite in my kitchen. Total cost 7k. I paid 5k upfront and suppose to pay balance upon completion. The guy attempted to fit and the section for the stove whilst placing on the cupboards, it broke. He says it's because the carpenters work on the cupboards wasn't good and his cupboards was not level, that's why it broke, but his granite on the underside wasn't level also, it wobbled when we placed on a level area. He says I must give him 1k of the balance to buy new material, which I did yesterday. Today he tells me he not willing to buy more granite with his money, and either I must pay for it or the carpenter. I asked for my 1k back which he did transfer to my account, so I have paid 5k and the job is not complete and because the stove piece broke, I still need to buy another 2.5 square metres. This guy didn't even use any glue under the granite so I still have to remove what he has already done and glue it....What can I do legally to get him to complete the job and to accept accountability for breaking the granite? He is a Muslim guy from Alberton, but he very rude, aggressive and arrogant to us and the boys he works with also.... They advertise granite machinery on gumtree and their website is www.granite machinery. co.za and their business is called granite express. Do not buy anything from them or neither get them to fit granite for you. Not sure of the fathers name, but the son goes as Zane (Zaynudeen Mansour). They are rogues. They don't accept accountability for their actions....