First of all: Did you check you ERB to make sure the flag is gone?
•Private First Class (E-3) - Four months TIG as a Private (E-2) and 12 months time-in-service (TIS).
If you've already talked to your team leader and he/she hasn't helped you, then inform your team leader that you'd like to talk to your squad leader about it, then your platoon Sargeant. Go up every link in your chain giving each link and oppertunity to resolve it. If you don't get a resolution or you're told you're not getting promoted because of (whatever) you have the option to use your 1SG's open door policy and make an appointment to talk to him/her about it.
It sounds like they don't want to promote you because of something you're not telling us.
Unlimately, No promotion is automatic for E-4 and below. you do your time, don't F**k up, be the best soldier you can be, and when you have enough TIG/TIS, a piece of paper comes to your commaders desk for him to sign to allow your promotion to go through (if you're not flagged or UCMJ pending). Most likely the cmdr will sign it, unless your NCO's give him the recomandation not to promote you.
If you're not flagged and your NCO's aren't taking care of you, ask your Team Leader if you can go to S-1 and/or see 1SG, so you can get this resolved