Turkish Airlines Damaged My Luggage and Refused Compensation

I traveled to Portugal with Turkish Airlines, paying a significant amount of money. Upon arriving in Portugal from Istanbul, I found my brand-new luggage broken. I immediately filed a report. They documented it and handed me a report, instructing me to apply online. During the online application, they requested numerous documents, all of which I uploaded, but the result was disappointing. They claimed that the damage was external and didn't affect usability, thus rejecting my claim. This is unacceptable. If that's the case, just keep breaking people's luggage and say it's still usable. This is absurd. If you can't resolve such issues for your customers, why are we paying you so much money? Every time I fly, I anxiously wait for my luggage, fearing damage. Every time, there's an issue. This was my first claim, and I got a rejection. I've never seen such negligence.