Do you know how to contact support via the in game help menu? Send a message to support reiterating what you said in your post, here, and ask if they can please restore your bricks.
It's early in the rollout of an important new game feature, can't guarantee any particular result but based on generally-positive experience I've had, sending tickets describing sort of similar mistakes I've made, and asking nicely for some help, I think the odds are decent you'll get the bricks back.
As for the other question, if/when you find a syndicate, try joining and if there's a hitch, send another ticket (but I think you'll be fine there, too).
Good luck.