use Modern::Perl;
use Data::Dump qw/dump/;

my %seen;
my %accounts;
my $g_total;

while (<DATA>) {
    next if $seen{$_}++;
    my ( $account_number, $amount ) = ( split /,/ )[ 2, 7 ];
    @{ $accounts{$account_number} }[0] += $amount;
    @{ $accounts{$account_number} }[1]++;
    $g_total += $amount;
}
say dump( \%accounts );
say "Grand Total = $g_total";

__DATA__
Joe Smith,12345678,44552,02/11/2011,no email, MA,USA,900.00,updated
Joe Smith,12345678,44552,02/11/2011,no email, MA,USA,900.00,updated
Joe Smith,12345678,44552,02/11/2011,no email, MA,USA,900.00,updated
Cindy Abbot,122233678,01122,08/09/2012,test@tok.com, CA,EUR,-120.00,updated
Mary Lou,33456678,44552,01/11/2011,no email, MA,USA,400.00,updated
SMith Doo,12345678,44592,02/11/2012,test@test.com, MA,USA,100.00,updated
Mario Att,00056789,022345,03/10/2010,no email, MA,USA,40.00,outdated
Mario Att,00056789,022345,03/10/2010,no email, MA,USA,40.00,outdated
Mario Att,00056789,022345,03/10/2010,ok@ok.com, MA,USA,40.00,outdated
Maria Smither,12345678,00051,02/11/2011,no email, MA,USA,750.00,outdated
Dan Smither,12345678,00051,02/11/2011,no email, MA,USA,250.00,outdated