I don’t think calling will help, unless you get someone in Ocean Ready. Phone prompts until you get them, OR. They seemed to be trained on the App, but MDR… not so much.
Do you have anything booked in the MDR? I had MDR TD and wanted to change it, had to cancel it all and book it again. It worked.
If you have nothing booked on the App…Did you try to book MDR on the website version of the App?
I probably would still check every day, to see if it opens.
If all fails, go to the MDR, that you prefer, first night, ask for their help securing reservations for your whole cruise.
Have others on your roll call been able to book MDR’s? You might ask if anyone does see one open, to post on the roll call.