Unfortunately, I don’t think that you’re alone.
I originally got my kit from Amazon, and I did have an issue with it, my power supply was DOA. I did get a response from the support form then, (Which was, “Please resolve this through Amazon”.)
I have since been trying to update my firmware, since there is an annoying bug in there somewhere, and I wanted the Marlin configuration file so that I could try a newer version. I have asked a couple of times and received no response.
I believe that this feeder arm is the same or at least reasonably similar to other versions for other extruders, and as such, you could probably purchase other ones for Bowden extruders. I have an aluminum Bowden extruder set, also purchased from Amazon. I could check if it is compatable, and at least that would get you ready to print.