We are purchasing a new construction single-family home from a builder. All our change orders thus far for upgrades included the invoice from the subcontractor/supplier where the cost was based on our selection (cabinets, countertops, etc.). We upgraded the master bathroom and the change order for the upgraded shower/floor tiles based on our tile and flooring selections is missing the invoice from the flooring/tile company. The builder is refusing to provide the invoice and asking us to make the payment without it. Can he withhold the invoice? What are our options to get the invoice for the additional work/materials we are paying for? PS: The upgrade was not based on a fixed fee. The upgrade price is dependent on our selections as was the case with the previous change orders where we selected the cabinets and countertops.