Cassandra, Sera, and Vivienne. Always. I stumbled upon that particular combo at first just because I usually always switch around party members a lot early on in Bioware games for no real reason, but i ended up sticking with them simply because of their interactions. The way Sera's dumb jokes annoy Cassandra and the way Vivienne's pompous attitude scares Sera is fucking hilarious.
Same thing happen to me, 4-5 months ago. Lucky I did not have any credit cards attached to my account. The only thing that happen was me getting the free to play game Fifa World and two new Russian friends on my friends list.
Lucky I could recover my account by resetting the password. Changed my username, email and password.
Enable two factor auth, don't store credit card info.