Who would I contact if someone in the Army is ping out personal info about me(details inside)?

If they are in the military also you can make a complaint with the military police, however, also you should talk to your base judge advocate, punishment is doubtful but you can get the person ordered to stop ping out the information. If they then disobey the order it is punishable under the UCMJ. Another option if you know his unit you might want to talk with your chain of command and have them speak to his chain of command on your behalf, whatever you do, do not contact his chain of command directly without the knowledge of yours.