Surprise price increase at till

Purchased planting equipment from Builders Warehouse Zambesi. The prices displayed were incorrect (explained as the 1% VAT increase), however the price increases were not 1%, e.g. purchased Herbs (shown as R20, R22 at the till - ********** 551721 that is 10% increase), planting pot (shown as R270, R275 at the till - ********** 68824 so a 4% increase). My total spend was R1091. I did raise with management and the answer was a small paper explaining that VAT will go up 1%.