Woollies consistenly *****ing/short food quantities!antities

I am rather tired of Paying a premium for food at Woolworths and the quantities are almost always less. I way the goods on occasion and it is almost always less than stated on the package. E.g paid R103,99 for cut mangoes. Package says mass 500 grams. When I weighed it at home with the package it was only 469 grams. *****ing 31grams! They do this to each and every customer and it significantly increases their already fat profit margin! . I have a lovely photo of this and will be taking more photos like this in future as it happens often!