Help: why my site has been removed from Bing's search results

Our website (link removed by moderator) have faced same issue recently. Raised ticket but no reply still now, I am really puzzled what's the probable cause.
We have another domain which we used as development website (link removed by moderator). We strictly mentioned in robots.txt not to crawl but still this website indexed and ranked better.

Site not at all showing.

Where as my development site  ranked extremely well despite blocking by robots.txt 

Only differences is we have used emoji in meta title in three different pages :magnifying_glass_tilted_left:  👍 .:trophy:  in Live site. Does Using Emoji in meta treated as spam and result removed for that?

Our entire website information manually gathered and not filled by any bot or anything.

Can anyone guide us to resolve this issues.