If the system was defective, the consumer should not have to pay for the shipping charge to return it or send out a working unit. The law requires the seller to provide conforming, working goods, so it is their obligation to get you a working system--they cannot pass part of the cost of fulfilling that obligation on to you.That said, if they are determined to charge you, it would take litigation to either recover your money or force them to send you a unit without charge; it may be that it is more cost effective to pay the shipping charge than fight about it.