OP skyblock's voting.

[KawaiiChan7]

I don't know about others, but i have lost a few vote crate keys and even a lapis key (from vote chest). My inventory usually has space, But i just get a message saying i got it when I don't. Can I fix this problem somehow?

 

[xXWitherBoyXx]

If you did not pay for the items you mentioned with real money, then I'm afraid your problem cannot be fixed. Just be more cautious and careful of your in-game items that you listed next time. Or your problem could just be a common glitch that will eventually subside.