Hello,
If your account/domain is hosted on a
shared server then, we won't be able to provide you the access of config.inc.php of PhpMyAdmin.
As you want to import large files over 50MB or greater than that then, you won't be able to do it from phpmyadmin.
You can upload that database backup file in .sql format under your web space you've with us and ask us to restore that file fro your specific database, so that it will be done in few minutes for you.
You can also contact us for this work on our live chat assistance which is 24x7..