How did they wander from Hashem?
Radak: They strayed from Avodas Beis ha'Mikdash to serve the calves. This is sin and rebellion against Me!
Why does it say "v'Anochi Efdem"?
Rashi: I wanted to redeem them from the evil in which they are. Radak ? I did not, because they slandered Me (refer to 7:13:3:2).
Malbim (12): If they would see what sin causes (their loss via wandering from Me), I would redeem them from Melech Ashur.
What is the significance of "Diberu Alai Kezavim"?
Rashi: They told Yirmeyah "Sheker Atah Medaber Lo Shelachacha Hashem Elokeinu Leimor Lo Savo'u Mitzraimah" (Yirmeyah 43:2).
Radak: They said that Hashem does not know and oversee their deeds, if they do good or evil. Therefore I did not oversee them, and "v'Histarti Panai Mehem v'Hayah Le'echol" (Devarim 31:17).
Malbim (12): Not only would they not heed My Musar and rebuke. They denied Hashgachah and punishment, and did not heed that the evil came to them because they wandered from Hashem.