I can feel your frustration especially when you have to deal with so many different contractors. I recently purchased 2 lamps of which one was a display unit as I couldn't wait for stock arrival (my electrician wanted to wrap up his work). During installation, electrician said one hook is missing so I suspected must be the one from the display unit. Went back to the shop to ask, the sales lady told me no hook. I told her cannot be cos the other new set got hook but she insisted no hook and asked that my electrician provide the hook instead. I wasn't satisfied so I pressed on and finally she just pushed a couple of hooks to me. I wasn't sure if those hooks can be used or not since she wasn't being helpful but luckily the electrician said can. Phew... Those lamps are few hundred ringgit too each. Not some cheapo lamp.