There's must be something wrong with your medical education credentials that's halting your ECFMG certificate.
The ECFMG will send you the certificate automatically once you meet all the requirements which are passing step 1, CS, CK, and completing your medical education credentials.
Once you finish the requirements it takes less than 10 days for the certificate to reach you via email and then a few days after that via FedEx.
Check your school credentials verification by logging in to your account in OASIS.
You may also find this thread useful: http://www.usmle-forums.com/ecfmg-forum/362-ecfmg-registration-steps.html