Couple things. First, the problem with the rust is that any method you use to remove the rust will also remove some or all of the gold etching on the blade. You need to make sure to dry the razor properly after every shave... before even washing off your face, etc.

Second- what shop that deals specifically with straights did you send this to to have dealt with? It is valuable for all of us to hear about this feedback. I'd be ****ed at the 'shop' for not taking care of my rust problem without an explanation if they said they would take care of it. Scratches on top of that is also something I'd bring up. On top of that, I've heard bad feedback about certain reputable 'shops' where it seems like they either don't test the blades well enough or just don't hone them well enough. Depending on what you say to all of this you should gather all the evidence (in your mind) and bring it up with that shop.