They put faulty items on sale

I bought their ******** that only worked for less than two minutes then stopped, changed batteries and it still didn’t work, sent them an email informing them and I sent it back, they said they took it to HQ for evaluation and told me that the batteries were in the wrong slots, how did it work then? Then they returned the same faulty item saying there is nothing wrong with it and it still doesn’t work! I’ve used three different sets of batteries.