Tml social addon , google send email as wordpress account username

Hello,
I have started working on a wordpress project. On this project Theme my login is installed to create custom login and registration interfaces, and the social addon was purchased to allow registration and login with social networks.
Everything works, but the problem that has just been noticed is that the registration with google registers the user but putting in the column “username” of wordpress the email address of the user, but for very long email addresses it poses serious problems of displays. Many of our users ask us to give them the possibility to change their username, but this is not by default allowed in wordpress. How to make that after registration by google, instead of email, the username is firstname_lastname?