Different prices on item..

Your service at the Phalaborwa mall is one of the utmost trash i have ever experienced. 1st the box states the item is 699 and yet when i get to the till im told i must pay 750. I asked why because it's not my fault the item went up and merchandiser did not change the prices as it was supposed to be. Your rude manager proceeded to tell me that my problem is i know too much. To add salt to the wound the security tag is not removed. Is this how your people treat customers and how many times do customers get treated like this?