As described by this user: https://answers.microsoft.com/en-us/bing/forum/all/website-still-delisted-in-bing-after-multiple/1413863c-ab48-4d3b-b77b-55555b7cf24d - it seems that there is no channel of reasonable communication with "Bing" after being delisted. I have suffered (and I'm still suffering) from the same problem.The best I've managed to do is contacting them by email and receiving some vague and unhelpful templated answers. It's really disheartening.
I'm wondering whether someone has ever had any success with resolving being delisted from Bing?