Have I done wrong in refusing to design a greeting card and an advertisement for a man who claims he treats with the Qur'an and that he is an astrologer, and is it permissible for me to refuse if I am forced to do so by my employer?

If a man performs Ruqyah solely with the Quran and is not known for sorcery, divination, or astrology, then there is no objection to designing a business card for him. His knowledge of praiseworthy astronomy does not harm this. However, if he uses polytheistic Ruqyah that involves seeking help from Jinn, invoking stars and constellations, sorcery, divination, and talismans, then it is not permissible to design a card for him. This would constitute cooperation in sin and aggression, as Allah Almighty says: "And cooperate in righteousness and piety, but do not cooperate in sin and aggression." One must not obey the employer if he orders this, for there is no obedience to a creature in disobedience to the Creator.