Moving on

So I tried T-Mobile for about 2 months and was disappointed in coverage in my area.  I moved on to another provider.  A full payment was taken by T-Mobile on the regular date, a couple of days after I started with the new provider.  I tried to look at my account to see if this was a payment in advance, I.e. for next month’s service or a payment for the month just finished.  However, they don’t allow access to anything in the account.  Nor can I remove my payment information from the account now.  I’m more concerned about the latter, especially now that they require a debit card rather than a credit card.  Is there any way to access payment information after leaving?