Not getting credits for my phone

Hi I signed up with a new plan with you guys all under the illusion that I was going to get a pretty good promo on the phone. Which is still not applied the store rep and when I called about it said it was going to be applied the whole reason I signed up with you guys was because the phone was going to be about $600 versus the $1,200. I was not told I could take two billing cycles for this to happen. This was not a trade-in this was a new phone setup so it feels weird it can take a few months. I would like to confirm I am actually going to get these credits? And I would like them apply it a lot sooner than what I'm getting.