If you are writing down people’s complaints and appeals as they are dictated by the people, and you do not know whether they are true or not, there is no sin on you for what you write down for them. Whatever sins or errors result from that without your knowledge, the sin is on the one who said it.
But if you know that what they are asking you to write down for them is a lie or falsehood, then it is not permissible for you to write it for them, because in that case it is helping them with falsehood and sin, and Allaah says (interpretation of the meaning):
“Help you one another in Al‑Birr and At‑Taqwa (virtue, righteousness and piety); but do not help one another in sin and transgression”
“And argue not on behalf of those who deceive themselves. Verily, Allaah does not like anyone who is a betrayer, sinner”
You should advise those who you know are lying and remind them of Allaah and of the warning issued to those who tell lies and make false claims, in the hope that they will accept this advice and give up their claims.
And Allaah is the Source of strength. May Allaah send blessings and peace upon our Prophet Muhammad and his family and companions.