Prices at the till doesn't match shelf price

I just had it now with Palms Spar today I went to by milk and bread for the week, the lady at the till charged me R 10-99 for a liter sachet of Douglasdale milk the shelf price R 8-99 when I questioned the teller she said its the price the manager was speechless I went to the shelf and retrieve the price still the manager did not say a word he definitely knew and was to ***ard to admit, My concern is that how many people are distracted by either kids wanting something or a spouse and don't even realize that they have been over charged This is the second time I been done in by the Palms Spar I bought 10 one liter sachet off milk at the shelf price R 89-90, the spar *****ed price off R 10-99 I would have paid R 109-90 the Spar would have ****** R 20-00 from me. The best part is that the low fat Douglasdale milk were sold out HOW MUCH MONEY DID THE PALMS SPAR ***** FROM THERE CUSTOMERS THIS EASTER WEEKEND ??? I have no choice but to contact the local newspaper and warn the public regarding the Palms Spar.