If both FADEC channels on one engine fail, the FADEC can no longer control the thrust. Nothing else will either.
ECAM:
T/L.... IDLE
ENG PARAMETERS...CHECK (as described above) I suggest also look at the rudder trim position?
IF ABNORMAL shut it down (which I assume means not at idle?).
If ECAM presents FADEC FAULT caution it might just be spurious - which you can determine from the presence/absence of indications.