This week's book giveaway is in the OCAJP 8 forum. We're giving away four copies of OCA Java SE 8 Programmer I Study Guide and have Edward Finegan & Robert Liguori on-line! See this thread for details.
The expected time to receive the certificate is within one month. However they can be a bit late. I got my certificate on the 30th day to be precise.
Have you registered yourself at the sun certification site and checked out whether it is showing as exam passed status against your name. If not, please do so. And then contact responsible people out at Sun.