Gravatar Really Linked to WP Login?

According to Gravatar, we can use the same login as our wordpress account, because a WP account is also a Gravatar account. That means I have lots of Gravatar accounts then, because I have lots of WP accounts.

I just want to change my Gravatar image, but I cannot login in with my recorded Gravatar login, nor any of my WP logins. And there is no Contact or decent Help.

They say I can reset my password, but that it will change the password to my WP account. Seeing as I use the same email for most of my WP blogs, I guess I won’t even know which WP account I have changed the password to.

Anyone know how I can sort out this mess?

thanks