Sascha,
Please check your mailbox, including the spam folder, for my response on March 20.
Nowadays enterprise email systems go overboard to protect employee
mailboxes. You might be better off using a public email provider such as
Gmail when communicating with AC support.
Usually you get a response from AC support within a few hours, oftentimes much faster than that. If you didn't, it likely means something's not right on your side. If that's the case, please use an alternative communication method (as you did). Please don't wait for 2 days, especially if you suspect a major issue.