Chainsaws

I REALLY like the saw and it's perfect for my limb management around the house.  I have a much larger saw I use for the larger cuts such as logs for firewood and so forth.  My new 240 has been used VERY little and it appears to have locked up tight on me  I have ONLY used Husqvarna brand 50:1 fuel in the equipment and I also used Husqvarna brand chain oil. It was running fine while using is over the weekend and just quit dead in it's tracks.  It sounded definable to internal cylinder failure...  Although I'm not an expert on small engines, I know quite a bit about engines for cars and when one lets go from the inside, it's pretty easy to tell.  The rope won't budge when I try to pull it either so also points to the engine being locked up tight.  Anyways, I went to Lowe's and they said I needed to contact you guys direct and to request and RMA # so that I could take my failed saw back to them and replace it for a new one.  Please let me know what I need to do about receiving an RMA #.  I have attached my sales receipt from where I purchased the saw, fuel and bar oil all in the same purchase.  I've used 1 full quart of fuel, and 1/2 of the 2nd quart I bought.  So that tells you the minimal extent of usage I've had on the saw.  I take good care of my equipment, it was not abused in anyway!  Thank you for your time!