thank you for your reply. We have already tried closing everything, logging out (and so forth, as described in the link above) numerous times. Unfortunately, a prerequisite in the other steps mentioned to find the error is to use a different account. We don't have another account available to do that sort of testing (excuse me, but is it really normal for customers to have more than one account?)
In the mean time I've been in three lengthy support chats trying to resolve the problem and we were promised a call back from a specialist on Friday last week. The support was friendly but, I'm sorry to say, dismal. No one called us.
After the these experiences we will most likely not prolong our CC Subscription next year. The other alternatives available are simply better, more reliable and cheaper. We are however open for help resolving the issue - maybe someone can show us it's worth sticking with Adobe.
Can you send me your case number so that I can understand why there has been a delay with your case? Some of the issues with XD are still under investigation, and it is possible that your issue is among them. To send a private message, click my picture and use the Message button. Will do my best to help.
Our case number is: 0222678949
We have received a reply from a representative in the mean time and the case is moving forward. If a solution evolves there I will update this query.