Hi!
I’ve got the same issue : lost my 180 BATs after a Ubuntu reinstallation and a restore of my wallet. I already posted in the forum 10 days ago and got no answer yet 
(post link : https://community.brave.com/t/lost-my-bats-after-restore-linux-ubuntu/)
I would really appreciate any help… or would like to know, at least, if they are definitively lost.
Thank you in advance.