Black Pearl Granite

We purchased a quartz orphan slab for a kitchen island for our townhouse from Black Pearl Granite. My wife, mother, father were present and the owner showing the slab told them that we purchase the whole slab as they can't make any vanities with it due to the size of island we were getting cut. The owner tells my family that we need 50% down and rest after installation. I go to look at the slab myself, like it and told by the office manager I need to put 75% down as the owner doesn't know its changed from the 50% down, as I questioned why so much. It clearly states on there website 50% down and rest of it apon installation. Then when it was close to delivery the owner states to myself and my wife that he did not say we get to keep the rest of the orphan slab and kept on denying that he said that. There was 3 witnesses that were there when he said we get the whole slab and we are paying for the whole slab. Then the office manager tried also to get myself to pay the rest of the purchase before installation and again states on website rest of purchase paid after installation. The owner as well tried to get the installers to take the slab away if we didn't pay for the rest of purchase before installation. We ended up paying for the rest of the purchase before installation as we didn't want to wait another 2 weeks to get a island from another company. The owner ended up not answering his phone after he tried get the installers to take island away, my wife was trying to work with him but he was being unreasonable and lied about what he said. To make matters worse the owner accidently phoned my wife and on voicemail and you can hear the owner and the office manager talking to each other and the owner second guessing himself about what he said to my wife, father and mother. We have no reason to lie and there were 3 witnesses that heard what he said. The product is great and we like the island its just sad the owner acted like the way he did and the office manager. There seems a real lack of communication between the two and lack of professionalism by the owner to customers.