Robertsons spices getting smaller by the day

I bought 3 x 1kg robertsons spices from Makro on Saturday 23rd of November and only opened my spices on Sunday 24th of November. I have been buying the 1kg for a few years now as these last me for at least 5 to 6 months. Lately I have noticed that these tubs are sometimes now full and have taken this up with Robertson a couple of times. Out of the 3 tubs that I purchased only 1 was full and the other 2 were almost 3/4 full. I don't know what to do anymore, I can't seem to find any other brand to replace Robertson, as I've been loyal to this brand for years. This is becoming very annoying that I have to complain almost every time I buy these tubs.