Brutal Fruit last straw

I went to Checkers Paarl van der Linge and bought the special on Brutal Fruit the cans were R150 for 2 six packs. The next day I heard that they were supposed to give me Brutal Fruit straws with the special but the lady at the till did not informed me for each 6 pack you get 2 straws. so in the last few weeks I went there and every time no stock. yesterday I went to Checkers Lady Grey and there were stock. I were so happy I'm going to get my straws. but when I look for my slip I lost it for keeping it almost a month, I could cry, the ladies there did not even listen to me, I franticly search my purse and bag but no luck.... they just give me an attitude for asking if they could give me the straws, who would do so much effort if not true. I liked to shop at checkers and Checker Liquor but after this i would think twice about their customer service