The lack of provisions is a fleet level thing, if you look closely at the fleet holdings interface there is a provisions tab for each of the 3 holdings.
The fleet has to queue provision projects in order to provide those provisions and every time someone buys something it uses a provision. The problem is provision projects give very little in the way of XP for a holding. So for the dilithium mine which we are trying to upgrade as fast as possible to unlock the best consoles and warp cores we cant queue provision projects. So right now the dilithium mine is not provisioned so you cant buy from it. As soon as it is levelled up we will immediately switch focus to provisioning elite fleet warp cores should become available in about 8 days and the mk xii consoles around 11 days after that.
The gist is dilithium mine is unavailable just wait till we have hit tier 3 on the red and yellow track before considering buying anything. You can find the current status on the fleet holdings menu ingame.