Yeah Yeah Yeah, lay everything at the feet of the customer. Unless SVS has some evidence that the customer took delivery of the item, it's up to them to find out where their item went. If they can prove the customer took delivery and is now making false claims then there's always legal action. SVS can even make it mandatory that the customer themselves must sign for the item.
What are you talking about? If no one answered the door AT HIS HOUSE, then they would not have delivered. If he has someone AT HIS HOUSE that signs for it, its safe to assume they have the right to be there. There is no need to require more than that. And btw, for those criticizing the lack of insurance, insurance would not pay out in this case given the facts above, at least until OP proves that he never received the sub (or puts some effort into it). We don't even know for sure that the package wasn't insured.
And SVS has no obligation, legal or ethical, to start tracking this down if the OP hasn't even done the tiniest amount of effort to find the subs himself through fedex. If OP really cares about this he would be working towards finding out what happened to the sub, not trying to get his money or two free subs from SVS or just badmouthing them without giving a chance. They replied to him asking very reasonable things, and his response was to come on here and denigrate them. That in itself is suspicious.