Dissatisfied Customer-Funki charger

Bought the funki 3-in-1 charging combo from there in July and one of the cables stopped working. When I returned it today with the slip the employee Ashante tested the other charging points and told me that the problem is my phone even when I should her that how come it’s working with the resent charger I bought from the same store. Instead of checking the fault on the iPhone point she was quick to point out that the problem is my phone even after I showed her that why is it working with a different charger bought at your store