and if there is a limit of 12 commanders how do i progress further in the game

iv been getting lots of battlecruisers and lost 3 commanders and i have an interagation room

i got 1 commander on 2 seprate missions but when i returned to base they where gone and inorder to get any further in the game i need to reserch more commanders.i also have all the latest updates. any ideas?

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