Penalising me for an inferior product sold to me

I bought a suitcase from Takelot with a six month warranty. Did my first trip overseas (6 flights in total). I noticed the zip opened when I checked in my suitcase, had to rezip to close it. Then the lock only opened after many retries (this happened twice). And on the last flight hope the one wheel broke off, and in addition the exterior of the suitcase has a tear that reveals the contents. In short it's a useless suitcase!

As it's only 3 months into the 6 month warranty I requested to return the merchandise. Takelot declined my return, their reason is that the wheel has broken off (they call this "user-damaged").

I called them to explain that I'm returning it precisely BECAUSE the wheel broke off after limited usage. They reviewed, then rejected my return again for the exact same reason.

What use is a 6 month warranty if its impossible to return a suitcase after 3 months that is so badly damaged after only 6 flights?

Takelot was always my favourite online shop because they were always willing to absorb the risk of online shopping with an effective return service. Sadly, after this shocking experience, I'm very unlikely to buy anything from them again.