Demo unit supp**** in place of new without inform

We are renovating an bathroom in consultation with a manager (Gus) from Italtile who has assisted us through the planning , including supply and sales of the materials and fixtures. We chose items which included a matching vanity and basin set, mirror cabinet and 2 tallboy boys cupboards. Through the process Gus informed us that he did not have stock of the tallboy units and we needed to pay and order them so we could secure 2 of the 3 units destined for the store. We were informed that the tallboys we paid for had arrived and we arranged for a pick up....we discovered immediately that one of the tall boys supp**** to us was loosely wrapped whilst the original was still in a box. We confirmed after it was delivered that the demo unit from the floor was packaged and sent to us instead of the brand new one we ordered and paid for without informing us. The project is underway and the Johan from Italtile was informed of this and his response was: \the demo unit is in immaculate condition and was on special"and therefore we can take it or leave it for a refund.(which implies delays and incomplete work) ...accepting it will be a breach of contract as we paid for a new unit! """