Contaminated Ice Block

I Bought An 5liter Ice Block From Big Tree Mall Maxbox Fish And Chips, The Cashier Said The Water That Was Used To Make That Ice Block Was Drinkable But After The Ice Has Defrost I Found That The Water Was Contaminated So Since They Did Not Give Me A Receipt I Didnt Have The Store Complain Numbers, I Went On Internet And Searched The Headoffice Contact, I Called And Explained My Problem But The Consultant Said He Cant Help Me