Products weigh less than displayed - overcharged!

I purchased a Christmas meat hamper containing 3 cuts from Woolworths in Lillies quarter. When I got home and unpacked I happened to add the weights of each cut as I packed them away. I found I was 0.5kg under what was displayed on the box. I then added the weight of the box in and was still 0.3kg under what I had paid for. That means an overcharge of around R50 per box sold as you pay per kg of meat! I returned on 21Dec and reported it to the store manager. I heard nothing back so on 7Jan I contacted her via email. She advises she has logged a complaint with Customer Service and would follow up but there was nothing more she could do at store level. At no time was I given the reference number. I finally gave up and just ate the meat cuts. What made me decide to report now was after having bought mince meat from Woolworths again. When cooking it there was so much water in it I had to drain it into 2 coffee cups to prevent me boiling my meat. Come on Woolworths! What happened to quality? Overpaying or paying for water is unacceptable. Hopefully others will see this report and consider weighing what they buy from you or rather buy from another retailed