Need Urgent Help

Dear Friends

Today our server was hacked by Bangladesh cyber security team.

and they deleted all files in public_html folder. i dont know how they do it. because we make all securities. even they deleted backup folder also. all backup is done by cpanel/whm only.

i need some help

1. how can i recover the files again. because all folders index.php and configuration.php is deleted. so i need to recover it.

if any one help me it will help for me.

thank you