Advertising under false pretence

I tried to purchase some items online and I came across the so called "promotion"... I added the items to my cart.. Added the coupon code.. After the code the amount got subtracted from my total. But when I tried selecting a delivery option there was only 1... There was no option to collect in store... The delivery amount charged was more than the discount itself... I thought maybe I was just struggling with the site. So I went in store. The same thing happened... Every time I app**** the code.. It gave me a ridiculous charge for delivery. Basically you're advertising under false pretence. Because when I removed the code I could collect in store. You should have just stated that there's terms and conditions... You apply a code... You can't collect in store