I agree with the general recommendations , donβt sigh anything, lawer up to protect yourself. Start looking for a new job.
Sometimes colleagues who are jealous of your success or have a specific agenda against you will do this. Look at the evidence and possibly challenging it should be part of your response. If the evidence does not hold out , counter file.
Win in any case and make sure the world knows about it through such forms so that others can benefit from it . ( if false )
Good luck