The only leverage you might have now since they are deneying it and already have their money is to start placing bad reviews of them online.
Top review sites are Google, BBB, Yelp, Houzz and Facebook ... read more
There are a few options depending on the circumstances, if the dog has scratched the slab and depending on material, you'll need an entirely new slab. You have the option of painting over the scratch, ... read more