1)
Why does he call them "Avadecha v'Amecha"?
1.
Malbim: They are Your servants - once You show them the proper path, they immediately repent and fix what they made crooked.
2)
How will Hashem show them the proper path?
1.
'Rashi' (Divrei ha'Yamim II, 6:27): E.g. in the famine in the days of David, You told them that it is due to "Sha'ul v'El Beis ha'Damim" (Shmuel II, 21:2). You show them for which sin rain was withheld (Radak - and teach them the good path and give rain).
2.
Ralbag: Through the punishment, they investigate their deeds and veer from the sin for which they were punished.