SuperSlim Tubs Underweight

Once again, trying to get a response from the Gatti factory shop in Nerissa Estate is impossible! I queried with them, more than once, the fact that their Superslim 500ml tubs are currently containing way below what they should weigh. Ideally, a 500ml tub of ice cream should contain 317gms of ice cream. These tubs weigh anything from 234mls to 252mls - with the tub! The tubs are not even filled to the brim anymore! There is zero response from Gatti!