I agree with you. One machine can be "off", but to have 2 machines unusable straight out of the box would make a reasonable person decide not to take that brand at all. Use your "broken record" skills when speaking to the vendor. Don't say "I would like a refund". Say "I need a full refund". Him: But blah blah. You: "I need a full refund". Him: But blah blah. You: "I need a full refund".