We are building a new house with a local builder. We chose from one of the offered plans by the builder. and have ran into an issue . Due to some miscommunication by the builder we now feel the need to extend the kitchen island. The house has been framed and is in process . The builder is not agreeing to make any changes . What are the options to extend the island using an outside vendor after the closing and match the granite on the counter top ? Is it even possible ? Will this be a good idea at all or will it be better to replace the entire island with a new extended one from another vendor after closing ?

Picture of how the island will look eventually as per the current plan ( without our desired extension )