Which supermarket is the leader in wrongly marked up prices leading to overcharging?

Ken68

Tempted to say Tesco, but rarely shop there now.
Occasionally have to go back to Lidl when reduced items are not correctly shown on the receipt.... and they are brilliant at accepting returned goods.
Constantly surprised at Lidl prices, for example, Evaporated Milk. 45pence per 410g's against up to a £1 elsewhere.
Evaporated milk is now my milk of choice saving approx. £73pa.
Every Lidl helps.