require "/home/path/to/ma/files/$_fileName.conf";

##</code><code>##

use strict;
my ($sth, $_mad);
$sth = $dbh->prepare(qq{SELECT * FROM `merchantAccounts` WHERE `u` = "1" AND (`volume_capable` < (`current_volume` + $_GrandTotal))});
$sth->execute();
$_mad = $sth->fetchrow_hashref();
$sth->finish();

my $_madFile = $_mad->{name};
use MA::$_madFile;

##</code><code>##

my $_madFile = 'MA::' . $_mad->{name};
use $_madFile;
# AND I've tried it this way:
use "$_madFile";

##</code><code>##

$_cardCharged = MA::$_madFile::chargeCard();