Actually, if you look at under your avatar, you'll see that you are described as a revoked NING. You were approved as a probationary member and the staff reviewed your membership and it was decided given your lack of any positive contributions to the community (no posts since April 28th) that your membership should be revoked.
You may consider this as being similar to where applicants are put on hold. You are free to resubmit a new questionnaire and go through the approval process again. There is no guarantee that you will be accepted if you do, however. I hope this clears up for you what has happened.