How to Delete Contacts on Yahoo! Mobile Messenger
Yahoo! Mobile Messenger is the mobile phone version of Yahoo! Messenger, Yahoo's free instant messaging application. One of the big advantages of using Mobile Messenger is that it is Web-based.
You do not need to download an app to your phone; you simply access Mobile Messenger through your Android's, Blackberry's or iPhone's Web browser. This helps keep the controls the same, so you can remove a contact from Mobile Messenger to remove it from your Yahoo! Instant Messenger account altogether.
Open Yahoo! Mobile Messenger.
Select the contact you want to delete to open the Contact Details screen.
Click the "Edit" button.
Click the "Delete Contact" button at the bottom of the screen.
Confirm that you want to delete the contact.