Disgusting service - Checkers Columbine Square

I am livid. I went into the checkers store by Columbine Square to do my groceries and upon passing an isle with travel mugs on I saw that the price displayed under the cups was 49.99. I took two cups as I was with my elderly mother. When I got to the till it shows a different price. I took a picture of the price and showed the teller to correct the price. She called her female manger to assist with the issue, and the manager proceeded to the isle and came back with a male manager who shouted at me and my elderly mother embarrassing us for what seems to have been a straight forward price to any customer passing those mugs. He proceeded to tell us while shouting that there was a sticker covering the correct price. I have pictures of the price and to any reasonable customer passing that isle the price that we saw should be the price we get the item for. Even the consumer protection act confirms that when you see a price lower than the one at the till you should get it at the lower price that you saw displayed. I am fuming because this man thought it was okay to shout at my mother and I causing us much distress and discomfort. I am utterly shocked and devastated at the unprofessional conduct of a senior officer of this shop that I frequent. I maintain that I want those cups for which I have pictures for at the price that I saw them at. Please fami****ise the shop management and staff on consumer rights.