(looks at picture of printer)
okay so you've got a weird bowden setup.
Quite why anyone would make an i3 clone that didn't have a direct drive extruder - is beyond me.
But they did.
Heat the hotend up to about 220 and Push the filament through the tube manually and see if there's any resistance at any point.
Also check the feed cog and wheel on the extruder itself.

People always leap to the 'it's buggered electronics' when usually it's something a lot more mundane.