Solved
I need the time shards!!!
When I was playing the challenge I was tired and not thinking so I made a new save for fun and gathered the rocks, so in one save I have all the materials but the time shards and the other has all th...
Never mind, I fixed it. I closed the game and reopened it and the option to buy the time shards from the mail box was there. I don’t know why it was bugged though.
