...
use DBI;

unlink 'file_01.csv';
unlink 'file_02.csv';
unlink 'new.csv';
open my $oFile, '>', 'file_01.csv';
print $oFile "Prefix,NumberRange,ChargeBand\n";
close $oFile;
open $oFile, '>', 'file_02.csv';
print $oFile "Termination,Service,ChargeBand\n";
close $oFile;

my $dir = '.';
...
    ) or die "Cannot connect: " . $DBI::errstr;

print "DBI            version: $DBI::VERSION\n";
print "DBD::CSV       version: $DBD::CSV::VERSION\n";
print "SQL::Statement version: $SQL::Statement::VERSION\n";

my $sth_match = $dbh_match->prepare(
...