False advertising

I think they do some false advertising especially with their loyalty program ... they send me a sms saying I qualify for a free pack of pampers, after 3 or 4 visit to different stores they keep telling me there is an error with the code. After spending 45 min at the till today they tell me the sms was sent in error!!! I need to buy 10 packs of pampers in order to qualify for the promotion... no correction sms or email was sent to me!?What a waste of time!