Sorting strings and create case based on keywords

I need to check the gmail inbox and read the email body of each email and create a case in CRM based on Keywords 'Billing and Loading', I have a working code for reading mails from Gmail but sorting has been the issue.

I have this code

 foreach($emails as $email) {

        $headerInfo = imap_headerinfo($connection,$email);
        $message= imap_fetchbody($connection , $email,1);

        if (preg_match('/Bill|load/', $message)) {
            if (strpos($message, 'Bill')) {
                echo 'billing related issue';
            }elseif (strpos($message, 'load')) {
                echo 'Loading related issue';
            }
        }else echo 'doesn\'t exists</br>';
     }

This code checks all the mails, finds the keywords but it checks for either Billing or Loading, not for both,. Please help me.