Add a credit card to your PP account.
There are several advantages.
Your payment will go to the seller faster and he can ship faster.
You will not overdraw the bank account you have attached to your PP account, avoiding bank fees.
You have a third level of Buyer Protection if the transaction fails. (eBay, Paypal , card chargeback).
The balance is apparently the first choice for payment, but to open a PP account you had to attach either a bank account or a credit card.
A payment that cannot be drawn from a Balance will be transferred to one of those, either the card or the bank.
You can cancel a purchase for a very short time, an hour or so after purchase, but after that you have to ask the seller to cancel for you.
She can do that as "at Buyer Request" with no penalty, but if she has been paid and has already shipped, that is not likely. Even a Buyer Request cancellation may cost her some fees which makes it unpleasant.
