When you transfer your site from one web hosting provider to another the e-mail addresses do not get transferred with it.
You need to go to the cPanel Control Panel that you have with the new web hosting provider and add those e-mail addresses to your account, with the password of your choice.
Please use a complex password and not choose one simply because it is easy for you to remember – because easy password probably means that it is also easy to hack into. Hence the password you choose should be a complex one as well as memorable.