A communications system may include at least one wireless communications device and at least one electronic mail (email) server for storing email messages for the at least one wireless communications device. An email relay server may detect a new email message on the at least one email server and, based thereon, send a short message service (SMS) notification with an original SMS identifier to the at least one wireless communications device. The at least one wireless communications device may detect the SMS notification and send an instruction to the email relay server to thereafter send any subsequent SMS notification with a different SMS identifier rather than the original SMS identifier.