Baking Powder issues

I recently visited Party Themes and I bought a kg of baking powder thinking I would save out if I buy in bulk. little did I know it flopped my cakes n cupcakes, it took me a day to realise that when I used another baking powder the cake was perfect. Please be advised to sell quality products as ur customers run a loss at the end of the day. Im still very irritated and disappointed with this incident