all i do is crunch numbers and eat wood glue.
It looks like ABS was the recommended material on the forum that the part was posted on. Here is the forum it was posted on and here is the Thingiverse page for it. It would be the “modified” file, out of the two listed. I am not sure about how the specifications work, like measurements, but it would be meant to fit a 6.5" car speaker if that makes sense. I know just about nothing about 3D printers.
If you’re that mad at them you should take differeng action. That’s how they learn. What they are learning from your current action is that you are okay with what they’re doing.