Bad service

In Checkers liquor Pmburg there was a special of Tanqueray gin and one gets a 6pack of pink tonic for free,bt the pink tonic was out of stock so then i lost my till slip to claim my pink tonic then i went to speak to the manager Ravi who didn't give me the time of day he was said no till slip no pink tonic end of story which was rude coz i dont throw bones how would I have know that the pink tonic was out of stock unless i bought the Tanquery gin i am sure there means and ways for Ravi as manager to check the system...pathetic service from Checkers liquor pmb.