Praise be to Allah, and may peace and blessings be upon the Messenger of Allah. To proceed:
The Day of Judgment is the day of perfect justice; no one will be wronged. Allah تعالى says:
﴿And We shall set up the scales of justice for the Day of Resurrection, so no soul will be wronged in the least﴾ [Al-Anbiya: 47].
And He سبحانه says:
﴿Then indeed, on the Day of Resurrection, you will dispute before your Lord﴾ [Az-Zumar: 31].
It is authentically established from the Prophet ﷺ that people’s rights will be settled among them on the Day of Judgment, even in cases of minor injustices, and that retribution will take place through good deeds and bad deeds.
Accordingly, Allah تعالى will grant every wronged person justice against the one who wronged him, whether the wronged person is a Muslim or a non-Muslim. This is part of His perfect justice. As for the precise manner in which justice will be given to a disbeliever against a Muslim, there is no text that explains the details. Therefore, one should not speculate about matters of the unseen for which there is no evidence.
It is obligatory for us to believe that Allah does not allow anyone’s right to be lost, and that He will establish justice among His creation on the Day of Judgment, while accepting that the details of the unseen are among the matters whose knowledge Allah has kept to Himself.
Whoever wrongs another person in this world should hasten to return the right and seek the person’s forgiveness if possible, and should not postpone repentance and the restoration of people’s rights until a Day when excuses will be of no benefit.
And Allah تعالى knows best.