Hey achrisley! Congrats (and/or crossed fingers) on the home-buying! We don't have a method to provide credit references, per se, but for postpaid customers each of your statements should reflect the payment that you made for the last period at the top - it will show the previous month's balance, the payment, and then the new balance. You can download .pdf versions of the last year's worth of statements from MyT-Mobile and print out the pages that you need!
T-Mobile does provide Credit Reference Letters but you have to call into Finance to receive them and they take 24-48 hrs to receive it in PDF form to an email address of your choosing. I've done it on two occasions when I was buying a house. Sorry for the late response, hopefully others will find this information helpful.