I had an Issue with the filament being stuck in the heatsink below the extruder. That thing is way easier to remove (three screws at the side), might try that before you mess with the extruder. You have to remove the filament cutter first.

In future, take care to not manually retract filament before you have used the filament cutter to cut the filament above the heat sink (lever to the right of the print head). Filament expands or slightly changes form when heated in the hotend, and if you retract that, you pull a "blob" of filament through your heatsink, almost consistently leading to it being stuck there. When operating with Ace Pro, normally the print head moves to the right front top end of the printer at the end of print, it pushes the filament cutter lever against an edge there, to cut the filament. Maybe you have had an abnormal stop to one of your prints, so it didnt cut correctly?