Canadian or American?
Canadian debit cards only take money from bank balances. American debit cards are also sorta credit cards.
Since she has a bank account, she can attach that to her Paypal account and pay directly from there. However, her Buyer Protection is restricted with just a bank account backing PP. (This is bad for her, good for the seller.)
She is best to add a true credit card (and not a prepaid card) to her PP account and pay through that.
This also has the benefits that the payment clears immediately (not true with a bank account) and that she has a second level of Buyer Protection from the cc (not true with a bank account).
Make sure she understands that you will have no access to her financial information no matter what payment system she uses.
And if she still can't work it out, offer her a Mutual Cancellation, if she seems sane and friendly. MCs release both parties from a transaction BUT both can leave feedback. Be cautious.
And if she really can't work it out and is belligerent, you can start an Unpaid Item Dispute after four days if you list on dotCA and two days if you list on dotCOM. No feedback unless she pays up.
