#!/bin/ksh

typeset chAddress=""
typeset fErrlog="/your/list/with/addresses.errors"
cat /your/list/with/addresses | while read chAddress ; do
     if [ $(grep -c "$chAddress" "$fErrlog") -le 2 ] ; then
          do_file_transfer $chAddress
          if [ $? -gt 0 ] ; then
               print - "$chAddress" >> "$fErrlog"
               mail_to_customer "$chAddress" "Sorry, your file transfer failed."
          fi
     fi
done

exit 0