Urgent! So I can not get my messages and answer my e-mails in Yahoo, or go to my contacts etc.This is the first time it happens and I am very concerned. Please give me your answer writing to my alternative gmail address: >Removed<
Please answer me as soon as possible.
Many thanks
Evangelia

Responders here don't write to emails, just below your question.
It's possible that your Yahoo has been hijacked. You should be able to report it to Yahoo on the home page.

First thing to do is completely clear your cache and start over.

Perhaps, you are not signed in.