It might pay to either take down the theme, or update it with a version that does not include the logo as it's a definite copyright violation and as far as I can tell (IANAL) couldn't even be considered "fair use".
Even if you are granted permission, you need to make sure that you're granted permissions that are compatible with the themesite's licensing (CC-BY-SA).
If that was to happen, great, though I personally think it's quite unlikely.
I realise that most people probably don't actually read the licensing details whilst submitting a theme, but it pays to, and would help to avoid blatant copyright violation and a moderator removing your theme entirely because of it.
[St.]