As a detached observer who has no former dealings with Warco, I've got to say that the fact that Warco supplied you with a duff mill did little in itself to lower them in my estimation; we all know to expect the odd bad apple.
What has lowered them in my estimation, to the point where they've currently dropped down my list of top places to buy machinery from (which I'm currently in the market for), is their response (actions, not just words) to finding out they supplied you with a duff mill.
If I had been Warco I would have arranged a next-working-day pick-up of your mill (regardless of what other machinery you are waiting for from them), told you whether or not a replacement was immediately to hand that could be sent out, and said that as soon as we had satisfied ourselves that the mill did in fact have the fault you say it does we would send out the replacement. Upon receipt, it would be unlikely to need more than one working day to verify or contradict your findings.
However good a supplier's products are, however good the reputation for build quality they have, those same goods can rapidly become unattractive to prospective buyers when the way the supplier is seen to deal with teething problems or faulty merchandise falls short of what reasonable buyers expect.
If the mill is indeed faulty, you will not lose financially. If Warco's customer service proves to be faulty as well as the mill, in the long run they may lose far more than you might have done.