Create an auto cPanel backup script

Question

I want to create a script at a cPanel / linux server. I want it to check on all possible errors.

    #/bin/bash
    cpanel_username=$1
domain=$2
if [ -z "$cpanel_username" ]
 then
 echo "no username given"
elif [ -z "$domain" ]
 then
 echo "no domain given"
else

/scripts/pkgacct $cpanel_username /backup/
mv /backup/cpmove-$cpanel_username.tar.gz /backup/$cpanel_username.tar.gz
FILE="/backup/$cpanel_username.tar.gz"
FTPFILE="$cpanel_username.tar.gz"
 
 if [ -f "$FILE" ]
 then
        ### FTP login credentials bellow ###
        FTPU="ftpuser"
        FTPP="ftpass"
        FTPS="host"
        lftp -u $FTPU,$FTPP -e "cd /hosting_backups;put $FILE;quit" $FTPS
        ######HERE I WANT TO CHECK IF THE FILE IS UPLOADED
        rm /backup/$cpanel_username.tar.gz
 else
        echo "couldnt take backup of $domain" 
 fi
fi

Also i would like to know if i can check if there is enough space for me to take backup. I want this to be done before the backup command.

I have tried many hours , but i couldnt make it . Any help is appreciated