DEA certificate is issued online AND a copy comes in the mail. I've applied for mine 4x now (once in residency, twice in fellowship due to an initial free one and then conversion to a paid one, once as an attending), and have always gotten it in less than 2 weeks. One time they had a question about my application, sent me an email the morning after I applied, I responded immediately and they issued it two hours later (online) with a physical certificate coming 2 business days after that. It is by far the most responsive part of the whole licensing cascade that I've ever had the pleasure to interact with.
That said, I've never tried to call them, so I have no tricks there.