someone on Roblox threatened to hack my account after asking for my Facebook

So i was just playing and hang out with new people in roblox and yeah i got along this one dude kinda well, he asked for my facebook so was like sure why not, so he sent my a friend request but before i even accept it, he just said straightly to me that “i’ll hack your account haha and take all of your money and everything” then after that his friend said something to him about the accounts he had hack and stuffs, so after i heard that panicked of course i did then i went in facebook, blocked him and did all the Facebook account privacy stuff so secure my account. I don’t really know how he can hack my account because i didn’t give him my password. What should i do now? What more should i do to secure my account from being hacked?

I’m 15