Hi @Peter918, just to confirm does the Face unlock not work at all or are you able to set it up but have issues while unlocking the phone? Also, have you recently updated your phone's software?
Apologies for the late response, are you still having issues with this? If so, can you confirm if you've tried to remove all settings and re-registered the face unlock to see if this helps?
Thanks, the next step would be to back up and perform a Factory reset. Have you also done this? Let me know if you need any help on backing up and performing this reset.