store disappointment

I saw a storage box priced R129 and asked one of the staff members to help me get it since it was high and I could not reach. Just before he gave me the box, he took out the price sticker and said the boxes have gone up. I told him that I want it at R129 since it is the price I saw but he refused. I asked for the manager and a lady came to assist. I told her the sort and demanded to be given the box at the price I saw but she also refused by saying the boxes were still going to be priced correctly , it is just that I came before the staff could change the stickers. I was so angry and disappointed that someone who is a store manager could not help me even if she is admiting that they were at fault. I was told to buy the storage box with the new price and I refused an decided to leave.