Missing Executrix ship shards and unable to move forward

Hello, I have Grand Moff Tarkins ship executrix at 1 star currently. When I go to the fleet challenge to get shards for the ship I have already completed Tier 1 but I can’t complete Tier 2 without Executrix being 2 stars. I need 15 shards to upgrade to 2 stars that I don’t have. I think what happened is I completed Tier 1 but I did not get the reward of 15 shards to get the ship to level 2 and therefore be able to do Tier 2. When I open the challenge it says no valid capital ship and that I have 4/4 of the other ships needed for Tier 2. 
It looks like the only way to unlock this ship is from doing the initial event before fleet battle and then the fleet challenge so I’m thinking I must not have got the required shards when I did these. I have had no issue with Home One or Endurance. 
I need to be able to continue on with this ship because I need it upgraded to continue on in the ship ability material challenge so I can upgrade my other ships.