iphone x TrueDepth camera Issue. Face ID disabled

for the past 1 month my iphone x is working perfectly fine. until one morning i woke up to check my phone and it suddenly says "A problem was detected with the TrueDepth camera. Face Id has been disabled". i tried to hard reset, reset all settings etc. but nothing works. i hope someone could help me with this. Thank you in advance.

by the way, if i bring it to a apple store or to the carrier where i bought it. how many days should i wait for fixing/replacement.