Restoring a Backup
/usr/local/cpanel/bin/restorepkg --skipaccount /backup/cpbackup/weekly/USERNAME.tar.gz
--skipaccount = don't create account, this is for restoring sites from backup that is already preset.
Instead of USERNAME.tar.gz, you can just specify path to backup, incremental. In this case, i just tar.gz the incremental backup folder as USERNAME.tar.gz and it worked.