We saw dimishing returns from Yahoo Directory years ago.
Rather than cancel our listing, we changed our Credit Card info to a prepaid card with a near zero balance, just to see what would happened.
We never received any correspondence from Yahoo on trying another card, and our listings are still there after a couple of years.
I just checked the Yahoo wallet however, and I see a bunch of unpaid invoices for Yahoo Directory Listings, however.
I beginning to beleive that Yahoo Directory is on auto-pilot. Nobody is maintaining it. Unpaid bills from Yahoo directory is not going to accounts or collections. Its just there to suck in all those automatic payments.
Well here's my experience with Y dir. I submitted one site to the dir back in about '05 or '06. I paid the fee and it never renewed. The site is still listed.
I submitted another site in Dec/08. It auto-renewed in Dec/09 which I got a refund for because it's not worth the annual fee IMHO. The listing is still there today, I just checked. So will it disappear? Who knows. I can tell you I did e-mail with another human regarding the refund so there is at least one person still working there ;-)
I'm not sure I've ever got a real visitor from there mind you... so as far as I can tell all I paid for was a little link juice.