Pnp long life milk

Bought pnp long life milk 6 pack, the milk is more water and see through than actual milk, and this for a so called full cream, contacted your offices they only want to refund for 1 litre milk, i need a refund on the whole 6 litres!! This product is disgusting and the service is bad too, they want to refund it back on the points card, i want to take it back to the store and give back the awful milk., in exchange for my money back. Can not wait for 3 days to use the money for other milk again. Poor product and poor service!!!