I just experienced the exact same issue. I loaded $100 was setting up an ad campaign and saw it was denied. I figured I’d check again the next day to see what the issue was; tried to login and received the same error message you described.
I called a few times no one can tell me anything and apparently my refund is on the way.
No appeal process just too bad so sad, no opportunity to have a discussion to see what the issue is and how to fix it, just kicked to the curb.
This is a legitimate small business operating since 2010!!
I was was really upset at first but now I’ve just put the money I would have spent with google; I was hesitant to spend it with bing to begin with even with the promotion ; but this entire situation is just so incredibly unacceptable I’m not even going to look back.
I searched to see if this has happened to anyone else and came across this.
I will not spend any advertising dollars with bing ads ever..