Here is the perfect way to export contacts from new Yahoo mail:

• Initially, you need to launch Yahoo email and sign in.
• After that click on the Contacts tab.
• Now, you need to click the Actions dropdown box.
• Later on choose Export.
• And then enter Export Now next to "Yahoo! CSV".
• Finally, after hitting Export Now, you will get a verification code. You have to write it in the text box which is above the security code box
• Enter Export Now.

With help of Yahoo Technical Support Live Chat Number and also following above steps export contacts from new Yahoo! mail account.