What Happens When a Chargeback Happens Through PayPal?

Facts
A chargeback occurs when a buyer requests his credit card or debit card company to reverse a transaction. A PayPal user can only issue a chargeback if he pays with his credit or debit card. A buyer can only request a chargeback if he never received the item, the item is defective, the item is completely different than advertised or the transaction was unauthorized. The buyer cannot request a chargeback if he decides he doesn't like the item. The buyer must request a chargeback by contacting his credit or debit card issuer, not by contacting PayPal.
PayPal's Response
Once a buyer requests a chargeback through his credit or debit card issuer, the issuer contacts PayPal and reimburses the buyer with funds from PayPal's merchant bank. PayPal will then immediately deduct the chargeback amount from the seller's account. If the seller does not have the required chargeback funds, the seller's PayPal balance will fall into the negatives. PayPal will email the seller and notify him of the chargeback. The buyer does not receive any notification from PayPal regarding the chargeback, and thus does not need to interact with PayPal in any way.
Seller's Response
The seller must login to his PayPal account and navigate to the 'Resolution Center,' where he can access the transaction in question. PayPal will request information regarding the transaction and will attempt to fight the credit or debit card issuer in the seller's favor, if the chargeback was unwarranted. The seller must provide the necessary information to fight the chargeback, such as delivery confirmation or the description of the item. If the chargeback truly was unwarranted and PayPal successfully fights the chargeback, then the chargeback money will be deposited back into the seller's PayPal account.
Tips
If you're a buyer and want to request a chargeback, you need to provide the credit or debit card issuer all pertinent information regarding the transaction in question: the date the transaction occurred, whether you've had contact with the seller and why you feel a chargeback is necessary. If you're a seller, you can avoid chargebacks by shipping items on time, describing items exactly as they are and initiating contact with the buyer.