After Just Six Months of Light Use, Nike Air Max Shoes Develop a Defect

I purchased a pair of Nike basketball shoes from Sneaks Up, and after only six months of use—specifically three hours per week in the gym—I noticed significant wear and tear on the inner lining, including fraying and tearing. Concerned about the condition of the shoes, I took them back to the store for inspection and a possible exchange. However, my request was denied, citing user error as the reason.
After receiving this initial rejection, I requested a second inspection, which was also sent back for review. Unfortunately, after 45 days without any updates, I called the store only to find out that my request had been denied again. It’s clear that the issue stems from a defect in the shoe's lining, which should not occur under normal usage conditions.
When I inquired about the second rejection, the store staff told me it was not their responsibility to notify me. As a customer, I find this response unacceptable, especially from a chain store selling world-renowned brands for thousands of ₺. Furthermore, it’s hard to believe that a well-known model like the Nike Air Max Impact 4 could deteriorate so quickly with minimal use.