Is working in an interest-based bank—as a customer service representative answering calls and providing information about loans and calculating their potential amounts without directly completing loan procedures—considered a sin against Allah?

Usury is one of the greatest sins and destructive acts. Allah has declared it a war against Him and His Messenger, and its prohibition is firmly established by the Quran, Sunnah, and consensus. It is not permissible to assist in it in any way. The Messenger of Allah, peace and blessings be upon him, cursed the one who consumes usury, the one who feeds it, its scribe, and its two witnesses, and they are all equal in sin. The questioner must repent to Allah and leave his job if it involves assisting in usury, even if he does not directly engage in usurious transactions himself.