Wireless email communications system providing subscriber account update features and related methods

A wireless communications system may include a plurality of mobile wireless communications devices each having a subscriber account associated therewith including a respective personal identification number (PIN) and a unique identification (ID). The system may further include at least one electronic mail (email) server comprising a database of subscriber accounts and for sending emails to and receiving emails from the mobile wireless communications devices based upon the PINs and unique IDs. The at least one email server may compare a given PIN and unique ID, based upon a communication from a given mobile wireless device, with a corresponding PIN and unique ID for the corresponding subscriber account in the database, and update the corresponding subscriber account based upon a discrepancy.