I think this is what you’re referring to,
“An issuer may not extend credit via a negative balance on the prepaid account except in several limited circumstances where the credit is incidental and the issuer generally does not charge credit-related fees for that credit; in these circumstances, the incidental credit is not subject to Regulation Z. These exceptions for incidental credit cover situations where the issuer has a general established policy and practice of declining to authorize transactions when the consumer has insufficient or unavailable funds to cover the transaction but credit is nonetheless extended as a result of so-called “force pay” transactions that will not take the account negative by more than $10 (i.e., a de minimis “purchase cushion”) or certain transactions that are conducted while incoming deposits to the prepaid account are pending.”
https://files.consumerfinance.gov/f/documents/20161005_cfpb_Final_Rule_Prepaid_Accounts.pdf
At this point I’m bowing out because no one here or at Apple has access to the financial information concerning your account with Green Dot Bank.
Contact Green Dot Bank:
by calling (877) 233-8552,
by mail for disputes at P.O. Box 9, West Chester, Ohio,
by mail for general customer service at P.O. Box 1070, West Chester, Ohio 45071,
visit www.greendot.com.
https://applecash.greendot.com/termsconditions/
For general information about prepaid accounts, visit cfpb.gov/prepaid.