Paying for granite never received and defective workmanship

I contacted Lisedi Granite - Address 3423 Albert Street, Randburg to install a new slap into my kitchen. The gentleman then sent me to Leasedi to do the work. I Paid JJ Swele Lesedi.

I accepted a quote for a new piece of granite and the installation. Leasedi came to install only for me to see it was a second hand piece of granite and that there is a crack 1 month after installation. After further inspection you can see that a crack was repaired at the bottom of the granite and that has now gone to the top. I then contacted Leasedi and on a view attempts he came out to inspect and said he did not know it was there. Not wanting to fight with him I asked him to please just install a new piece so that it can be fixed. He gave me a price and I paid him promptly. He promised he will come and fix before easter. it is now 5 May 2023 and ever day he tells me he is on his way just to never pitch up. I have asked him to refund me, but to date no luck. He tells me he is not a Tsotsi and is an ethical business man. Well his actions speak louder than words 6 weeks after payment. Do not use these guys, they install inferior products and then just run away. Leasedi is also a tiler, so who knows what type of work he does.