Poor service

Bought a 30 litre over sink geyser from Chamberlains. The salesperson at Chamberlains indicated the valve to be installed and this was installed. A separate valve in the box indicted it was only required to be installed for the European market only and the plumber did not install it. When the geyser stopped working three days after installation, Ariston void the warranty because the valve is not installed although there is a pressure reducing valve installed. All the instructions were followed to install the unit and they just merely wash their hands to fix it. Stay away from these products.