我记得我之前写过，好像找不到了，没关系，再水一贴。
购买地址 https://weidian.com/s/1873369936
https://weidian.com/item.html?itemID=2882553848
官网解释：
https://support.t-mobile.com/docs/DOC-1356
Refill automatically
For your convenience, and depending on the type of plan you have, you can either set up AutoPay, where your account is refilled every 30 days, or Auto Refill, where your account is refilled based on the frequency you choose. You’ll need a credit card, debit card, or your checking account information.
Automated refills can be set up through one of the following ways:
My T-Mobile
Log in to your My T-Mobile account online.
From the Welcome page, under the My Account status, select refill account.
On the Refill Account page, under AUTO REFILL, select Sign up.
Select Credit or debit cards or Checking account to enroll.
Enter checking account details or card details, such as billing information, name, expiration date and address.
Below the payment details, in the Sign up for Auto-pay section, choose one or more of the following options:
AutoPay: Occurs monthly on the renewal date.
Auto Refill: Allows you to schedule your payments.
Add extra funds: To be used towards additional monthly usage costs.
In the Save payment information section, select Continue.
Connect Me
Access Connect Me on your device.
When the prepaid account dashboard appears, tap Add/change monthly plan.
Choose desired plan, then tap CHOOSE MONTHLY PLAN.
Review the Auto Pay Terms, then click NEXT. Auto Pay is required for prepaid auto renew data passes.
Enter payment information, then tap NEXT.
Review terms of service, then tap AGREE.
Review payment summary, then tap PLACE ORDER. Wait for changes to apply.
Call the Refill Center at 1-877-720-5195
Refill online
You can refill your prepaid account online or through My T-Mobile. Here are a few details to keep in mind:
Maximum refill amount of one transaction is $150.
Multiple transactions may be completed in one day.
Total account balance can't exceed $1,000.
Refill by phone
You can refill your prepaid account on the phone by calling the T-Mobile Refill Center. Just dial ADD (233).
Purchase refill cards
You can purchase refill cards online, or you can purchase them at a T-Mobile store or an authorized retailer. Find a refill location near you.
Change automatic payments
You can update your credit card details when you are signed up for automatic payments.
My T-Mobile
From the home page, click Auto Refill.
Click Manage Payment Options at the bottom of the page.
Click Edit under the current card information.
Input the new card information.
Click Continue to save changes.