Ok first can you move the collet freely ie does it rotate without power if so then remove the cable from the VFD and check with a Ohm meter what the resistance is between each pair of the three wires going to the spindle.

It sounds to me you might have a bad soldered joint in the plug but check from the VFD end before you remove the plug.


The spindle would make a noise and not spin if one of the wires was disconnected BUT be carful as you could destroy the VFD.