Manual price increase of barcoded item

On choosing an item I noticed that the price tag had another price sticker stuck over the original swing tag. I removed it to check what the previous price would have been to find it was R199 where the added sticker was R220. How do items go up in price in store? So I went to the till and they scanned it only so tell me it was now R260. When I complained they quickly removed the sticker and told me I could get it at the original price, nervously fumbling, trying to change the computer price. The cashier was confused and was being instructed by the floor salesperson, who was suddenly nervous. This feels like a **** to me.