Are Mormons Christians or a lesser sect, and how can one refute their claim that Islam refutes their book?

Islam is the true religion that Allah has approved. It is based on the worship of Allah alone and following the Messenger Muhammad, may Allah's peace and blessings be upon him. The ridicule of opponents does not harm a Muslim; rather, a Muslim invites people to Allah, practices his religion, and says: "Indeed, I am among the Muslims."

The Christians are polytheists because of their worship of Christ, his mother, and the cross. Therefore, do not pay attention to their ridicule and do not argue with them, lest they confuse you with their misconceptions. If you can transfer from the school where you are being harmed, then do so.

The Mormon sect appears to be a branch of Christianity. Islam does not refute the Gospel that Allah revealed to Jesus; rather, the Quran confirms it. However, Islam refutes the religion of the Christians who took Christ and his mother as gods, and it refutes the corrupted Gospels. Christ disavowed these polytheistic Christians in religion and will disavow them on the Day of Judgment.