If the email address is the thing to determine uniqueness then you can build an assoative array keyed by email address. In the loop to build this array you check if an item with the email address exists, if not then add it, if so then just increment the amount.
$exploded_data = array(/* etc as you have exploded on comma then bar (|) */);
$final_data = array();
foreach($exploded_data as $row)
// Note you probably need to replace $row['email_address'] with the index the email address is at, which would by 1 looking at your source data (i.e. $row).
// If record with that email address exists then add to amounts.
$final_data[$row['email_address']['amount'] += $row['amount'];
// This is the first time we have encountered row with the email address so add whole row to the final_data array. Key by email address.
$final_data[$row['email_address'] = $row;
// Then use final data as wanted.