If all you are outsourcing is the deep etching (and it sounds like that's the case here) then you would do all your editing on the images first. You would save your master PSD files as usual.
Then you would save those files as maximum quality jpegs, and send them off. They would send them back, also in jpeg format, but with the clipping paths included.
Is that what they did? Made the background pure white? That definitely wasn't necessary, they shouldn't have done that.
Are the clipping paths saved in the files? If you open a file, then go to your Paths panel, is there anything there? If not, they cocked up.