Help with Halo 3 ODST?

[Erd]

i have halo 3 odst and i beat the game on normal. I wanted to replay mombasa streets so i did but i didnt like it. I pressed save and quit and now it wont let me replay missions. When i click a mission to replay it says "This will erase your campaign progress, but not your Visr comm data. Continue" please help

 

[ThE x SpaRK]

That will let you replay it, it's saying whatever mission you were playing, will have all the progress deleted from it.