Pull & Bear Pants Have Crooked Side Seam, Return Denied

Two days ago, I purchased a pair of pants from Pull & Bear. Since they were too long, I had the hems slightly altered. However, when I tried them on at home, I noticed that the side seam doesn’t run straight—it veers to the side. Unfortunately, I didn’t notice this defect before altering the length.

When I tried to return the pants, the store refused, claiming they couldn’t accept them because they were altered. How can such a defective product even be sold? This is unacceptable. I expect Pull & Bear to take responsibility for selling a flawed product and allow me to return or exchange it. Please respond to this issue as soon as possible.