Use this email sales@canaan.io to contact them you can also contact them through their social media accounts below

- https://twitter.com/canaanio
- https://www.facebook.com/Canaansupercomputing/?modal=admin_todo_tour
- https://www.instagram.com/canaantech/

If you bought the miner directly from Canaan and if it's not yet beyond the 3 months warranty you are lucky you can still get support from them but if not try to flash your unit or use the FMS tool and try aging.