I have been dealing via email with an itunes agent and they still aren't aware of the problem. All charges I disputed with Paypal I have "won" and they have issued 10 out of 11 refunds. The 11th being the only true authorized payment. I am still waiting and will wait for those transaction to post to my Paypal linked account. IT will take longer to get a refund than it will taking the money authorized or not. Thats a fact of life and this forum wont change that. Fee's are how banks make their money on the little guy. It stinks.
To all that used Paypal they "found" in my favor within a couple hours on the weekend so I would make sure you use that dispute process to your advantage. As one poster said you entered into an agreement with Apple/Paypal and your bank. Not much you can do from the bank side other than to notify them. Stop payments will cause a charge probably larger than the debit.
@justiniowa I feel your pain it is not a great feeling being overdrawn especially when it is is no fault of your own. If I were you (and I am taking my own medicine) I would disassociate ANY payment with Apple until this problem has been addressed. That only means removing any form of payment from your account and not killing your account completely (saving your downloads). Forgo adding any other payment method until this blows over otherwise the same thing may happen as it has for me and others on this post. More charges. They have some serious code problems on their system they need to fix before I attempt adding more payments.
Just my two cents (which Apple was kind enough to leave me)