O2 Sensor problems of the 2008 Volkswagen Rabbit

I bought Volkswagen Rabbit 2008 model two months ago, and less than 4,500 miles the oxygen sensor wire ripped yesterday while driving. I took the car straight to the dealership. This morning I received a phone call telling me that the cut was due to an animal!! (so it wouldn't be covered by the warranty). I look at this wire just before dropping the car at vw, and concluded either a manufacturer defect (assembly plan, manufacturing. . . ). I was furious at their conclusion, because this could be due to a lot of factors (definitely not an animal!), but vw America must have instructed their dealership to conclude in this way. Because the same thing happened to my daughter 2008 vw jetta (same engine but 2 weeks older than mine), and her vw dealer (different than mine) concluded it was an animal. I strongly doubted that, but conceded it could happen (I never saw the broken O2 sensor in her car;) but when saw mine, I knew it was not an animal: no chewing mark, no marks around the spot denoting the presence of any animal. I have a mechanical engineering degree with 7 years experience at a shop working mostly on german cars. I was surprised to have to doubt the integrity of vw America, but they did not give me other avenue to discuss this matter, it we say so and you have to pay.