Just call them. I don't know about UMD, but Brown said that those not notified till now are waitlisted. If anyone is not going to Brown, do let them know soon. I know it feels empowering to have many acceptances at hand, but you will be going only to one, so please let them know.
I have similar problem with JHU transcript issue. I wrote to them about 6 weeks ago and never heard back. And they insist on not sending more than one query. Highly unprofessional. It really is not like they are doing s a favor by responding our queries. We are paying to be ensured of that.