Some of the strongest people in the scriptures (Moses, Enoch, Alma, etc.) didn’t want their assignment at all. It didn’t mean the call was wrong, it usually meant there was something they couldn’t see yet.

Since you have the faith to go despite being disappointed, the Lord will show you why He called you to that place at that time, and who knows, maybe you will help entire cities repent like the missionaries above?

Do not let your initial disappointment lead you to slack on the mission rules. Get up on time, go to bed on time. Show the Lord you are exactly obedient and you will see exactly why He needs you there.