Some plastics are a pain to mill. You have to have enough RPM to cut cleanly but not melt. Those eccentrics might do well from a 3D printer.
Getting returns from these companies is a pain. When my 500mw laser module died I did not bother, I upgraded it with a 2W diode and new driver. I have 4 Laser modules now. 1 stock 2500mw, 1 stock upgraded to 2W, two built from parts, 1 2W and a 3W TTL. When my MOSFET went out on a L7 I bought a replacement and then repaired the first one. I have lost several stepper drivers but had extras. With two machines I have lost twice the parts! LOL