Partially filled gas cylinder

I bought a sealed Sodastream gas cylinder from Pick n Pay (Vanderhoffpark, Potchefstroom) on 7 February. The gas in the cylinder totalled 70 gram, instead of the promised 270 gram. That same day I lodged a complaint through [URL Removed] which was ignored up to now. This is not the first time that I bought empty cylinders, but the first time that I determined it to be empty, or partially filled, before breaking the seal.