Denial from DHS

I recently got denied when clearance from DHS and they closed my case is there a way I can appeal this? I recieved a letter from them stating the reasons why and they said it was their final decision. What should I do?

What were the reasons why?

Misconduct and dishonest conduct.

In the letter, they should have stated the appeals process. (work quickly because you may only have 30 days to respond)