Tesco has been censured by the Advertising Standards Agency over its Price Check campaign.
In the advert the grocer claimed to be cheaper than its rivals or refund double the difference, an offer that some wily shoppers took that advantage of.
Details of products which were significantly cheaper at Asda through short-term promotions were shared on internet forums allowing shoppers to claim money back. Tesco was forced to back-track and put a £20 cap on refunds.
Advertising watchdog ASA ruled that the supermarket did not make the cap clear.
The ASA said: “We considered that the £20 limit was a significant restriction likely to affect the average consumer’s decision to shop at Tesco during the promotional period.
“Because the restriction was not included in ads…we conclude that they were misleading.”