Q: What do we do if the moon for Shawwal is sighted and we have only fasted 28 days?
A: If the moon for Shawwal is sighted on the 29th night (evening of the 28th) it means that you started Ramadan late. You are to break your fast the following day for Eid and then make up 1 days to complete 29 fasts of Ramadan. Source: Hidayat al-Raghib
This answer was collected from HanbaliDisciples.com. The questions have been answered by Imam John Starling.