I always check the prices most carefully, both as they appear on the till-display while going thru & on my receipt. Only time I have ever found a mismatch in 50 years was when the price had been increased of a sports item which had a manufacturer's price printed on its packaging, but the store had shown a higher price on its display. I queried this at the checkout and was charged the manufacturer's printed price. This was at the Bar Hill, Cambs, branch of Tesco.

Otherwise I have never experienced anything to match what appear to be Topsie's unfortunate experiences.

~Michael~