Refused claim

So I bought a TV last year December not even 5 days old and a dead pixel appears lucky I could still return it to the store and got another one. So this time around its 4 months later and I have what seems to be an ant in my back light that's what they are saying. And now refusing to honor my warranty claim. My question is how did it get there and its clearly speculation because they didn't even Investigate to see if it is an ant or if the panel is lose. They are so quick to sell you **** and when it breaks they turn a blind eye to it. A dead pixel appeared on my screen I'm waiting to see what the say about this now