In the plan and on the contract I assume what you received and was installed was not what you paid for and agreed to.
I will also assume that you told them when they were installing it or when they finished that they had made a mistake.
You can rely on the contract you have and take the matter to NCAT and request that they replace the kitchen or repair it.
The following link is the law as it applies in Australia.
Bit you have to notify them of the issues and give them the right to come repair it. In relation to the thickens of the stone you can ask for a reduction in price as well.
I hope this makes sense and is of assistance. if there is nothing further
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