Defective Product Purchased On Trendyol Was Not Accepted For Return

I purchased a pair of bamboo pant liners and a sleeveless top from the NT Underwear store on Trendyol and received the items on June 28. Since I didn’t use the items right away, I washed them only when I wanted to wear them, and after washing, I noticed that the side seams had abnormally curled inward; this clearly appears to be a manufacturing defect. There is also a small hole in the pant leg. I messaged the seller about this issue on June 19. At first, I was told to submit a return or exchange request, but when I explained that I couldn’t do so because the return window had expired in the system, I didn’t receive a response for some time. Later, I was informed that my items would be shipped back, but despite nearly ten days having passed, no action has been taken. When I wrote again today, they said they could not help me this time because the return period had expired. Even though it is clear that the defect in the product is related to manufacturing quality and became apparent after washing, I do not consider it fair that my legitimate complaint is being ignored on the grounds that the return period has expired. I have photographs clearly showing the defects in the product and am prepared to share them with the company if necessary. Even though the return period has expired, I demand that my defective product be accepted for return and a refund issued, or, if that is not possible, that it be replaced free of charge with a defect-free product.