They are automatic if you select that you want it.
Since I have it off by default, I don;t get C+ unless I go into My Trips, Manage Upgrades, and select the flights I want. If it clears, OK, if not, I go back and deselect it to avoid the middle seat issue.
So OP, are you sure you have C+ requested? If so, something is wrong...maybe just no inventory...but not if you can call and get the seat.