in that case, you need to dissesemble the extruder and check:
1) the grub screw on the worm gear is fully tight and the gear is not slipping.
2) there's no bits in there blocking stuff
3) that nothing has broken.

I mean the last 2 are pretty obvious. A lot of people don't even realise that the drive gears are attached to the stepper motor shaft with grub screws, and they can work loose.

Hopefully it won't be too tricky to takev apart :-)

If looking for videos or how tos, the mono price voxel is really a rebadged flashforge adventurer 3 (they are literally identical)
And flashforge are much better at producing support materials than mo9noprice :-)