I was in the same boat. This was the outcome:
Thank you for providing clarity so that I can further assist you. Regrettably, since your 2 Million Miler status was earned prior to March 1, 2019, you are not eligible for this gift. Nevertheless, I would like to extend a goodwill gesture as I can only imagine your inconvenience. I’m sending a $300 Delta Choice gift. You will receive a Delta Choice gift code, from [email protected] in a separate email within three business days and you can select the gift card of your choice within 60 days of receipt. Included in the gift option are several merchants that you will be familiar with as well as our Delta gift cards. Once redeemed, the gift cards have no expiration and may be used by anyone you wish. You will want to add this email address to your list of accepted addresses. Our Delta Choice gift code email will include a customer ID and instructions on how to redeem the gift. Please check your spam folder if you don’t see the email in your inbox.
Again thank you for your ongoing loyalty.