What does Numbers 21:29 mean?

You’re in trouble, people of Moab. The god Chemosh you trusted couldn’t save you. His followers ran away, and your daughters and sons ended up as prisoners of war. We crushed your cities, just like we did to Sihon, king of the Amorites. Numbers 21:29 - Modern Text Bible

(This verse is a taunt against Moab, saying their god Chemosh failed to protect them, and their people were taken captive, just as happened to the Amorites under Sihon.)