1)
What is the meaning of "Tesimenu Madon li'Shchenenu"?
1.
Rashi: You made for us quarrels with all our neighbors; Yavan confronted us.
2.
Radak: They confront us constantly - "Ish Riv v'Ish Madon l'Chol ha'Aretz" (Yirmeyah 15:10).
3.
Malbim: Sanvalat and Tuviyah quarrel with us, like it says in Nechemyah Perek 6.
2)
Whom do they mock?
1.
Radak: This is a euphemism, as if they mock themselves. Really, they mock You, and say that You cannot save us.
2.
Malbim: Our enemies mock our neighbors, that they quarrel with a lowly nation like us.