Oysho Leggings Durability Issue: Quick Wear & Tear

I bought leggings from Oysho, and even though I used them for a short time and took good care of them, they wore out quickly. At first, I didn't pay much attention to the small signs of wear, but they got worse every time I wore them. I purchased the leggings from the Oysho store located at Bursa Sur Yapı Brand Shopping Mall. The store staff didn't even bother to assist properly; they were rude and provided no assistance. Getting in touch with customer service didn't lead to any improvement; I was simply denied outright. I expect a company of Oysho's size to respect consumer rights and make it easy for me to exchange the product.