Any decent business would have eaten the loss on anything that has been already ordered.
That's the price of selling something you don't have all the materials to make.
Telling you that they need 30-40% margin is downright idiotic.
Any sensible person would have known you would take this right to the internet (as you did) and tarnish their reputation (which you also just did, rightfully so).
So to make a couple more bucks on one single sale, the entire pinside membership is now reading about it, likely costing them multiple times that amount of money.