Hey there, and welcome to Support!
snn_555 is right, the promotions page is where you'll want to check your offer status. When the home page loads, right below the T-Mobile logo in the upper right, click the option for Promotion Status. Then you can enter your tracking number on the far right. Just to warn you (and prevent a panic attack), on the Reward Tracker page that opens, it will say $0.00 while your submission is processing. You can click View to see more details about the offer, timeline, and status.