Change my billing date

You need to call Tmobile.

https://www.t-mobile.com/support/account/whats-impacting-your-bill

Can you switch my billing date to the 1st of the month? That's the only way I can pay my bill on time!!!

Like I said, call 611 or contact T-Force.

I tryed its not showing to make pay arrangements when I click make payment

Support staff here cannot access your account. You need to call 611 or contact T-Force.

To contact T-Force

Go to the Contact Us page and use the Facebook, Twitter or Google Plus link under in the “Social Support” section.

AFAIK, you can't change the date that you cycle billing cycle ends. If you can't make a payment on time, you can ask to make a payment arrangement.