I'm currently wondering, if a single coil in a 3 phase stepper had failed, would it run but with vibrations?
If you've got a multimeter, disconnect the motor wires at the driver, and compare the resistance between all the wires.
The datasheet lists resistance as 2.48ohm per phase, but I don't know if that will with coils connected (i.e. give an actual reading of 2.48ohm) or for each coil individually (which would give a reading of about 1.66ohm ).

I'd also unbolt the motor and try running it. It's only the 4 bolts that hold it in place. As long as there's no marker paint on the bolts and you don't damage anything, the supplier will be none the wiser you've had it off.
If the motor runs rough disconnected from the slider, then you know that's the main problem.


For a replacement, I'd probably go for a 200W servo, and combine it with a planetary reducer box to give more control (3000rpm is a bit much for something with this short a travel directly coupled to a 10mm pitch ballscrew!)
Have a look a http://servo.xlichuan.com/ for ideas. Servo motor size would be 60 frame, and you'd need a new adapter for fitting the motor, but that's nothing major.
You can buy Lichuan servos via Aliexpress - https://www.aliexpress.com/store/1907567
Although I think all their gearboxes are built to order. The last one I ordered added a couple weeks delay to the order, as they had to build the gearbox.