false advertising

On the 29 Mar 2016 I went to the above mentioned shop to purchase the weekly shopping. In the store was a poster almost the height of a grown man claiming that if you purchased 4 Frankie products you were entitled to a collection of magnets. These could be collected on the way out. After payment of goods we were told that this no longer applies. If this was the case then the board should be taken down as this is enticing people under false pretense to purchase more than what they normally would.