LCD screen

I have a Dell Dimension 15 5000 series laptop, non-Touchscreen, that developed a white area in the lower left hand corner of the screen after about 3 months of owning it.  Because I was using for school and work could not send it in until last week just before the warranty was about to expire.  Dealing with India tech support was a challenge to say the least.  After dealing with 2 hours on the phone and emailing multiple pictures it was sent in and now they are saying the screen was damaged due to pressure put on the screen.  This laptop was never dropped, nothing set on it so I don't understand how I could have caused this.  I asked for pictures of the so called damage and everything takes 24 to 48 hours because the India tech support has to contact Houston so this is very frustrating.  My question is, what causes white or light areas on an LCD screen and how do I deal with US support so I can understand the individuals I am talking to?  Thank You.