Shaving Gel again loses pressure and useless even though its hardly been used

I have bought shaving gel from Dis-chem a few times and each time (eg Blade), I end up not being able to use more than half of the shaving gel as the pressure inside the can seems to disappear while the can has only been in the bathroom in Pta and is far from being expired. Sending them email is a waste of time as they do not bother to respond. S