Lacoste Clothing Came With A Hidden Defect

I bought something in March and only wore it once. Even though it's a Lacoste item, it ended up having a little 1-2 cm gap, which obviously means there's a problem with the material. I sent the thing back to the Eren store where I got it from for an exchange. But they just sent back the same thing with no explanation. Me and my partner dropped some serious cash, around 15,000 TL, at their store back in March. We ain't gonna accept such a dismissive examination. They asked me to send it again. I spent some time and sent it again to the address on the invoice. So, like, they're saying it was supposed to go to the Lacoste warehouse or something. they're asking me for it again, for the third time. Are you serious? Why am I put through this hassle when I paid like thousands.