Only Allah can punish anyone for not accepting Islam as faith. Its not the job of a person.
"So render good counsel, for you are simply required to counsel, and are not invested with the authority to compel them. But whoever will turn away , Allah will chastise him with the most terrible chastisement." Quran 88:21-24
"Had your Lord so willed, all those who are on the earth would have believed. Will you, then, force people into believing?" Quran 10:99
"There is no compulsion and coercion in regard to religion. The right thing has been made distinct from the wrong thing: now whoever rejects taghut and believes in Allah has taken a firm support that never gives way." Quran 2:256
One may keep in mind that Allah is just and says that no one will be wronged on the day of judgement.
"And We do not lay on any soul a burden except to the extent of its ability, and with Us is a book which speaks the truth, and they shall not be dealt with unjustly." Quran 23:62