The ruling on whoever stones the Pillars before Midday on the second Day
Question :
What is obligatory upon whoever stoned the pillars during the morning time on the second day of the 'Eid, then after that he found out that the time for stoning is after Az-Zuhr?
Answer:
Whoever stoned the pillars on the second day of the 'Eid during the morning before midday, he must repeat its stoning after midday on that day. If he does not find out about his mistake until the third or fourth day (i.e., the 12th or 13th of Thul-Hijjah), he repeats its stoning after midday on the third or fourth day. He does this stoning after midday before he stones for that day during which he is reminded (of his mistake). If he does not find out until after sunset on the fourth day, he has not stoned and therefore he must slaughter an animal at the Haram and give it as food to the poor.
Source:
The Permanent Committee
Fatawa Islamiyah, Vol. 4 Page 254