The blessings and curses of Torah are guaranteed to Israel, but the curses are temporary. #israel will repent. She will return to #torah. No matter how badly Israel has strayed from God's instructions, she will be restored. The partial return of the Jews from Babylon was not a fulfillment of that promise. They weren't ready yet and so God sent them back into exile. There is another, much greater restoration still to come.
Deuteronomy 30:1-5