What is the contact email of Yahoo small business billing?

I received a wrong bill $35 for a domain that Yahoo does not support almost
for a year since the domain was transferred to a new
owner. I immediately cancelled my account as I noticed the unwanted
bill in my bank statement. Thus, I couldn't get any result from
HELP/CONTACT US and I cannot 'Reactivate a cancelled account' (possible because the domain does not belong to Yahoo and they realise this at the point of reactivation).

How can I contact the billing service?
once more, smallbusiness.yahoo.com/contactus/ does not work:
Sorry!
We offer phone and email support only to Small Business customers, and our records don't show any Small Business products associated with your Yahoo! ID.

Sorry you've had trouble getting in touch with us, Alex. Please email us at domains-support@cc.yahoo-inc.com. Don't forget to include your Yahoo! ID and domain name.