I have been eating a dish from a restaurant for i while now because I heard that it was halal. But i recently found out that this restaurant is not halal in my country. What should I do?

All perfect praise be to Allah, The Lord of the Worlds. I testify that there is none worthy of worship except Allah, and that Muhammad is His slave and Messenger.

If it turned out to you that the food you ate in that restaurant is not Halal, then stop eating there in the future, and there is no sin on you for what you ate in the past because you did not intend to eat Haram. Allah the Almighty says (what means): {And there is no blame upon you for that in which you have erred but [only for] what your hearts intended.} [Quran 33: 5] Ibn Kathir said in his Tafseer: "Allah forgives the mistake, as he said ordering his servants to say: {Our Lord, do not impose blame upon us if we have forgotten or erred} [Quran 2:286], and it is reported in Sahih Muslim that the Messenger of Allah, sallallahu ‘alayhi wa sallam, said: “Allah said: I have done so.” Also, it was reported in Sahih Al-Bukhari, on the authority of Amru ibn Al-‘Aas, said: The Messenger of Allah, sallallahu ‘alayhi wa sallam, said: “If the ruler (judge) passes judgment and strives to reach the right conclusion and gets it right, he will have two rewards; if he strives to reach the right conclusion but gets it wrong, he will still have one reward." According to another Hadith, "Allah has forgiven for me my nation their mistakes and forgetfulness, and what they are forced to do.” [End of Quote]

Allah knows best.