yahoo server in blacklisted?

[Best]

I have been a long time customer of yahoo. I send emails from my yahoo account to my husband’s account he has with nucleus.com, but he has not been receiving them for some time because Yahoo mail server was put on blacklist as per this message I received from nucleus support personnel:

"Yahoo’s email server: nm20.bullet.mail.bf1.yahoo.com has been added to a public blacklist (which is utilized by many email providers worldwide to prevent spam)

This specific blacklist is bl.spamcop.net

This is due to an influx of spam originating from Yahoo’s mail server. Yahoo would need to investigate, then resolve this issue, and apply for removal from the blacklist. Nucleus does not have the ability to remove them, nor do we have the ability to resolve the fact that their server has been sending out spam emails.

The mail server blacklisted is only one of many outgoing mail servers yahoo uses so some of your email may be getting through, but when yahoo directs your email through this specific mail server: it gets blocked by the blacklist."

My question is what is Yahoo going to do about it? It’s extremely inconvenient, as my emails seems to be directed through the above mentioned server 99% of the time. How can I contact Yahoo support, instead of scrolling through suggested topics that do not cover my issue? Thank you. Helena K.