Why is Dan not mentioned

Why is Dan not mentioned as one of the tribes of Israel in Revelation 7? When Jeroboam I was king in Israel (1st Kings 12: 25-33) Dan gave up his inheritance as a tribe of Israel. The tribe moved from Israel and went North to Laish. Here they settled and began to practice idolatry (Judges 18). They willingly gave up  their right to be Gods Children. At Which, Manasseh one of Joseph son is listed in his place. Joseph also had another son call Ephraim. Manasseh and Ephraim were each considered half tribes. But with Dan and Ephraim being disqualified Manasseh became a whole tribe. We also see that Joseph also became a tribe again. Ephraim lead Israel into Idolatry and they where disqualified by God. Both tribes had once been in the grace of God. But they gave up that right to be God’s saved. Someone might say they were never really saved. Someone might say that was Old Testament, we live in the New Testament age. How would you answer those statements? The example of these two tribes serves as a reminder to us that we have the right of free will.