This is put up right at the top to help a desperate blogger who accidentally deleted her Blogger account and need help to get it back. So a quick section right at the top first and this post will be edited later:
First, Blogger usually will advice that the blogger probably has forgotten he of she has created more than one account and will suggest going to Forgot password and see if you can make some headway there.
Failing that, try problems. You may be taken on a merry-go-round, but perhaps if you have problem but come across a set of choices where there is a "report a bug", select that and see if you can connect to Blogger Support.
The rest of the post is not ready. Got to rush off to a gathering to support some people who had been unjustly arrested. Hopefully, this will lead to some solution. If not, leave a comment.
The rest of the post will be edited later:
This is a tough topic because the goal post keeps changing. I have made 3 previous posts which have multiple editing and updates because Blogger Support keeps changing the way they can be contacted. The previous posts are
Contact Blogger Support
Contact Blogger Support Part 2
Problems signing into Blogger Dashboard, don't see your blogs in Dashboard (note: Blogger Help says often the reason is because the blogger may have created 2 Blogger accounts and forgot about the other one, and therefore don't see those blogs in the forgotten Blogger account in the signed-in Blogger account. You may test this by