originaly i had this problem but then while i was fooling aroud with the cheat for adding money, i bought all the upgrades that i could buy (which wasnt all of them). shortly aftr that i noticedd that the missions app/tab in the phone menu was grey and unuseable. I thought that the last mission never went avay no matter how many times it was completed. Now i can call any homie that i previously wasnt able to call. right now i have shaundi, pierce, and viola. the last upgrade i used before i noticed that the homies worked was the City Takeover and i used it on a random district. that couls have been what fixed it but i dont really know for sure.