Is it permissible to work in conventional banks as a customer relations manager?

It is absolutely impermissible to work in usurious banks. Anything connected to usurious contracts is even more prohibited because it is a direct assistance in sin. Allah Almighty says: "And do not cooperate in sin and aggression." The job of a customer relations manager will not be free from assisting in or promoting usury. Therefore, this offer must be rejected.