Selling inferior product

I bought an inferior product - a cable for my son’s phone which he actually showed me to be a little loose. I told him to be careful with it as I didn’t want to have to make the trip to the store again. This was my own fault. Because less that a week later, the head of the cable broke off in the charging port. The store feels this is negligence on our part but needs to run through bureaucratic measures to assess whether this in fact falls within their warranty guidelines.

The cable isn’t very expensive. But I am annoyed that this was not considered - selling something inferior and they can tell that this is impossible to break in less than a week.

It would have been better to go to a gadget store - they accept responsibility.