Can’t Sign Into My Y! Small Business Account To Update Credit Card #?

I have my free Y! id, but I also have a Small Business account, with a domain & email account associated. My bank recently changed my credit card number, and I simply need to sign into my Small Business account to update the number.
When I go into My Account, and ask to Manage My Premium Services, it asks me for my password again — fine, but no matter what I do, it won’t go past the screen asking for my password! I’m not entering it incorrectly (& my capslock isn’t on), because I’m not getting an error message. I’ve tried an incorrect password, and then I do get an error message. It just keeps asking over & over again for my password, but never brings me further so I can update my account.
I’ve tried contacting Customer Service 3 times now, but they’re not responding… I’ve tried arranging a callback (they never called) and tried through the online Help Page.
Can anyone offer some advice? I really don’t want to lose my Small Business domain name & email account!