No fine print for my rewards

On Friday I tried making use of the special on huskey dog food advertised as you entered the shop. A friendly chasier informed me that the store loyalty card and the my rewards cards are separate promotions. I left the 16 tons of dog food until my rewards card was activated. On Sunday I returned to the store. I purchased the 16 tons of huskey only to notice that the my rewards discount was only valid for the first 10. Nowhere was it advertised that<br> you could only buy 10. Not all the staff was aware of this either. The first person referred me to her manager. After waiting a while for him to appear he informed me it was only valid for 10 items and that I couldn't split my transaction in 2. When I pointed out that none of the adverti*****ts had a limit that a customer could buy he then went to his manager for advise. After waiting yet again he returned stating that the manager said the system is set like that at head office and there was noting they could do but report the query. As I had been standing around for a period of time already I was not willing to waste any more time to leave my details.How many people are being caught by this gimmick if they don't check their slips?