Praise be to Allah, and peace and blessings be upon the Messenger of Allah.
Whoever did not receive the message of Islam, or received it in an incorrect manner, will be tested on the Day of Resurrection. Whoever obeys will enter Paradise, and whoever disobeys will enter Hell.
This is indicated by the words of Allah تعالى:
﴿And We would never punish until We have sent a messenger.﴾ [Al-Isra: 15]
Therefore, the one who did not receive the message will not be punished before the proof has been established against him. Allah تعالى knows best the condition of His servants and is the Most Just in His judgment.
And Allah knows best.