Is a person held accountable for the infidel thoughts and imaginations that occur to him against his will, and are these whispers considered disbelief despite attempts to repel them?

These whisperings are from Satan's cunning to divert you from worship, and you must not pay attention to them; rather, repel them from yourself. Your dislike of these whisperings is a sign of the sincerity of your faith, as the Prophet, peace and blessings be upon him, said: "That is pure faith." Their cure lies in resorting to Allah Almighty, increasing supplication, seeking refuge in Allah from the accursed Satan, and occupying oneself with beneficial knowledge and righteous deeds. If Satan sees the servant's steadfastness and patience in obedience, he will turn away from him.