bricked my old LG, i told them it just stopped working (tried rooting it and completely broke). I kept turning it on and off till the battery drained and it showed nothing when powered up, then sent it in and said i'd made no adjustments and that the phone was almost new. Got a new phone completely free, never heard anything about rooting.
Call customer support and say the same thing, pretend to be an idiot and just say "It stopped working". It might work for you too.