can I go back to an earlier version of yahoo mail where that was an option?

My all yahoo mail

I can't get into my yahoo email. Msg I get is "can't get mail. Connection to server failed. Customer service couldn't help and told me to go to Technical support, but when you call they say you will have to pay a monthly fee for premium help. What gives???

If you are using a laptop or desktop computer, switching to basic Mail may solve your problem. 

 •Select Settings (located in the upper-right side of the page)•Scroll down and click More Settings•On the left side of the page click Switch to basic Mail

Once Yahoo upgrades to a new format you can't get the old one back. They remove it from their server.

It's no longer possible to switch back to the classic version of Yahoo Mail. It has been discontinued. There are currently 2 versions of Yahoo Mail for desktop web browsers that you can use: Basic Mail and the full-featured Yahoo Mail: https://help.yahoo.com/kb/sln15936.html

Starting January 31, 2019, the classic version of Yahoo Mail will no longer be available. At that time, you'll be upgraded to the latest version of Yahoo Mail or basic Mail.

Not possible, what you see is what you get