If you think that your Yahoo account is not secured then first visit the Yahoo setting page and set up your account and if you are not able to do so then just take the Yahoo Help in order to secure your account. You can take Yahoo Help by calling at +1-855-479-3999. Feel free to contact us as we are all time available to provide the best customer care service.  https://www.mailsupportnumber.com/yahoo-customer-service-number.html