Yahoo Small Business email account not accessible


New Email
I have two emails accounts one with and one with Yahoo Small Business related to a domain lodged
with Yahoo. Mid-April I was requested to update e-mail accounts which I did. Everything went fine with the e-mail. Unfortunately the Yahoo Small Business account has not recognised my new password and
my emails are no longer accessible. I have been able to talk to customer care on the phone (after lengthy waiting) and they promised that they would do necessary to allow me to access my mails again. Nearly three weeks have passed and nothing happens. What can I do? Advice is very much appreciated.