Okay, I just resubmitted my CSE just now, and I got an automatically generated reply within seconds of submitting it.
When I was submitting it, I noted that I had submitted this same CSE before, but that I had not received any intimation whether or not it was accepted, not even an automatically generated reply, and that, owing to the importance of the documents I was submitting, I was resubmitting them to be sure. I also added a screenshot of the 'Success!' screen I got when I submitted my CSE last week, to ensure that there was no doubt that I had submitted a CSE when I said I had.
Basically, if you have not received an automatically generated reply, chances are it might not have gone through, and the backend systems may have been down. I would personally recommend a resubmission.