I have been trying to get my Bing account working again for a while. I recently got his message.
This is Joemar with Bing Ads Support. I hope this email finds you well.
Thank you for your patience during our investigation.
Our goal is to make sure that all your concerns will be addressed and that all is well on your Bing Ads Account that is why I attempted to call you today at 04:20 PM PST on the phone number ending in 4899 but I am unable to get through the line.
After further review, it appears that your site did not meet the standards set by Bing to remain indexed in Bing.com the last time it was crawled which is impacting ad delivery as well.
We are not able to provide specifics for these types of issues but we recommend that you review our?Webmaster Guidelines, especially the section?Things to Avoid, and thoroughly check your site for any deliberately or accidentally employed SEO techniques that may have adversely affected your standing in Bing and Bing-powered search results. Once your site is re-indexed by Bing, your ads should begin serving again in 1-2 weeks.