Checkers staff telling blatant lies

Last month Checkers offered Pampers Premium Nappies for 99.99 on a promotion. I went to various stores who were all out of stock (Kenilworth, Parow, Weltevreden). At all stores I was offered a rain check. As one of these rain checks expires on the 28th I went to Checkers Kenilworth today to purchase the nappies. As there was no stock on the rack, I asked an assistant to check their stockroom, The first thing she asked me is \ do you have a rain check"on which I rep**** yes. she left a little while came back with a supervisor and said the supplier is out of stock. It didn't feel right to me that she would ask me about the rain check in the first place"