Any Technies Who Can Help Me? Desperate

I have a big problem with Blogger.  Someone managed to get their email address into my Google Blogger account.  I have to sign in using their email.

I've tried and tried to solve this, using Google help, but unable to get anyhere.  I'm afraid my blog is going to disappear.  Does anyone know how to contact someone at Google directly?  I can't find a way to communicate with anyone.

Or--if anyone knows how I can resolve this issue, please give me a clue.  Meanwhile, if my blog disappears, you know why.

Thank you, in advance.