Walaikumussalam
If an oppressed person complains about the oppressor and mentions his acts of injustice, it is not Ghiība. As the Almighty Allah (SWT) says, “And whoever defends himself after his being oppressed these it is against whom there is no way (to blame). The way (to blame) is only against those who oppress into and revolt in the earth unjustly, these shall have a painful punishment.” (Surah Ash-Shūrā 42: 41-42)
But remember if you add anything then it will be sin.for that reason I made request to you forgive him and stay blessed
Wassalam