Bing vanished my website!

Deal with it the same way you'd deal with Google dropping you-try to figure out why. It sounds like your site is indexed. This is what i'd do:

For starters, look at your backlink profile and be honest with yourself. Are these quality links?

If they're not, try to remove the spammy ones and work on building good, one-way links. If you have a poor link profile, its not uncommon for your links to lose their value (because they were not quality links).

When investigating your links, look at your anchor text. Is it diverse? Are you using one text too much? Anchor text variation is HUGE.

After looking at your links, look at your sites on-page seo. H1 tags, description, etc.

Lastly, look at your marketing efforts overall. Are you writing fresh, original content on a frequent basis? Are you using social media? Search Engines love social media signals and sites with fresh content.

I wouldn't worry too much about Bing because its so unpopular. How are your rankings on Google? I'm assuming not great if your site is having problems with Bing. Let me know if you need any help.

From my experience with Bing they have got quite strong filters, if you drop a load of links very quickly with no social signals you can disappear, but you may reappear in a few weeks time..