Upload & Sell: Off
Nobody wants to hear it, but as we do repair work where I am employed, the reason behind not selling parts is simple. Most parts make little or no money for the repair facility but labor does make money and that's why they are in business. Also, every part you sell is one less you can install for your customers and this results in unhappy customers. Not everyone is a do-it-yourselfer. Think about your own profession and I'm sure you can relate to that concept.
Luckily except for nikon parts, dickish repair shops that don't sell parts are easily replaced with the internet.
It's always interesting when a business turns away customers that are already there, with money in hand, willing to spend it, even at a hefty markup just to get them then and there.