Receiving an auto-reply seems not to give any guarantee, take a look at this user experience. I would try to send it a 2nd time and see if you get an auto-reply (or maybe 1st check your junk mail or spam filter).
Finally got the following reply from Oracle, phew.. seems like they do respond to emails..
Thank you for your assignment submission and completing the essay. Your assignment has been sent to our assessors for grading. The scoring process may take up to six weeks depending on submission volume.
Once your assignment score is returned, we will contact you with the results. Please let us know if we may provide further assistance.