I found the true problem to be the plastic pan isn't suitably level. there is a railroad tie supporting one corner that it 1/2" above the concrete pad that supports the rest of it.
when i put force in one direction it feels quite firm, the plastic pan grips the machine well, and i can see why a level installation doesn't need to be bolted down. But if i rock it in the other direction it shakes and wobbles easily with very little force, like a chair on uneven legs.
So I'm going to take the warped plastic pan, place it on flat concrete, prove my point, and not pay a thing, infact their getting a bill, i should not have to educate myself in home repairs to get a quality job the first time, thanks everyone for your help.