Revocation is supposed to be filed with you, the party originating the transfers, not with the receiving depository financial institution (the one holding the deposit account). If she revoked the authorization properly, you should refund her money. If she did not, you don't have to. Now you have notice, you can't send any more debits.
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John S. Burnett
BankersOnline.com
Fighting for Compliance since 1976
Bankers' Threads User #8