I need help with my BOGO deal

Hi! I’m extremely confused and could use some advice. I joined T-Mobile in September of last year using a iPhone 15 bogo (P517) I can’t find any info about the deal specifically regarding what I agreed to. The problem is I’d like to start paying off more on one of the phones so that our bill goes down. One of them is $34 and the other is $5 - if I pay toward the one that is $34 a month will it mess with the promo and make me owe more? I keep trying to look it up on the old promo page so I can see exactly what I agreed to but I can’t find anything.

To add: yes I know it was stupid to agree to it without looking first but my sister was in dire need of a new phone especially since she was starting school again in a few days and hers would not turn on much less work properly. 😭

I just want to see if I can lessen the burden of this bill because I can’t afford paying off both phones at the price they’re at. Please help!!