The format of your email address is determined by your JPA status at the point you entered the system.  

Users who are not in JPA initially are assigned a 'Cadetmail' address. This format cannot subsequently be changed to 'Armymail'. There is no difference in function between the two, it is purely a difference in name. 

More support can be found here. 

Please note: Armymail/ Cadetmail is managed by the Army Digital team rather than the Cadet Digital Helpdesk, so we may need to pass your ticket to this team for resolution. 

It is not possible to prevent all spam/ phishing emails. These emails should be deleted, ideally without opening. 
 
If you have clicked any links/ opened any attachments/ replied etc, please inform the Helpdesk who will refer this to Army Digital for investigation.  This is in case you have let some malware onto the system or leaked sensitive data. 
 
You should also let your Unit Security Officer know so they are aware.