As far as I know, you can go either way after receiving the competitive letter. Many people get waitlisted, and a few get accepted. It seems that most people who get outright accepted do not get the letter. It may be that your application was reviewed already, and they could not decide whether or not to admit you, and deferred the decision to a later date. In either case, you can still get in. Good luck.
Oh, and just from personal experience: I applied to RWJ two years ago, received the competitive letter, was waitlisted and ultimately not accepted. This year I applied again, did not receive the competitive letter, and was accepted.