Are you aware of this thread: Dual Extrusion Head: Heat creep discussion thread
Snapmaker admitted that there’s a problem with the first batch of Dual extruders. There’s a repair kit: Replacement Kit for Dual Extrusion Module (VAT Incl.) - Snapmaker EU
You may be eligible to get it for free, reach out to Snapmaker support for that.
How can this not work? It’s a bunch of metal you screw to the machine… Please describe your problem if you expect help.