Non-Receipt of Vefification Code

I bought a new Samsung Cell phone, the apps were transferred from the old phone to the new one. On my old phone, I could open my yahoo email without using a password, only had to click on the mail icon. If attempting to access my via a computer, etc., I would enter my email address, then click "Next", a message would be sent my cell phone asking whether or not I was trying to open my emails, giving my the options of a check mark for yes or an "X' for no. After clicking on the check mark, the yahoo email on my computer would then open up. If on another computer other than my home computer, a verification code would be sent to my cell phone, instead of the verification code going to my new phone, it is stated to be going to my old (closed) phone, How can I solve this problem? Thanks.