Product: Money transfer, virtual currency, or money service

I have an account in PayPal. On XX/XX/XXXX I decided to pay with my PayPal account, for service ( airplane tickets ) provided an online travel agency, the amount of XXXX USD ( XXXX EUR ). The transaction is registered in PayPal under number XXXX. To complete the transaction PayPal used my available balance ( XXXX USD ) and the difference ( XXXX USD ) was withdrawn from a credit card ( ending in XXXX ), which I have not authorized PayPal to use. 
On XX/XX/XXXX, I have added the card ( ending in XXXX ) that was valid thru XX/XX/XXXX to my PayPal account. When the card validity expired, I have not taken any actions to renew the details of the card in PayPal, and to grant authorization for using the new card that is valid thru XX/XX/XXXX. Anyway, the renewed card was used by PayPal in transaction XXXX. 
According to the PayPal 's User Agreement effective from XX/XX/XXXX ( attached in the present complaint, also available on the following URL XXXX XXXX XXXX  ), at the time the old card had expired, the following terms applied to linking and unlinking credit cards to a PayPal account XXXX ********* Link or Unlink a Payment Method You can link or unlink a credit card, debit card or a bank account to your PayPal account as a payment method. Please keep your payment method information current ( i.e. credit card number and expiration date ). If this information changes, we may update it using information and third party sources available to us without any action on your part. If you do not want us to update your card information, you may remove your payment method from your PayPal account. If we update your payment method, we will keep any preference setting attached to such payment method. You may choose to confirm your card, so that we can verify that the card is valid and that you are the card owner. 
********* According to this agreement, PayPal may only update the credit card number and the expiration date. It is not stated that PayPal may update the card security code ( CSC ) of the card, which is necessary for verification and making online transactions with the respective card.

Also according to this agreement, I, as an user, may choose to confirm the ( updated ) card, so that PayPal can verify that the card is valid. I have never confirmed the updated card details with PayPal. 
Furthermore, on XX/XX/XXXX I received an email from PayPal ( attached in the present complaint ) with the following information : ********* We noticed that your card ending in XXXX is about to expire. Please update the expiry date and card security code ( XXXX ) as soon as possible so that you can continue using it with your PayPal account. Be sure to activate your new card with your bank first. 
********* As seen from the email, I was requested to update the XXXX in order to continue using the card with my PayPal account. Not following the instructions from the email should have made the usage of the card with my PayPal account discontinued. As mentioned above, I have never taken any actions in order to confirm or verify the renewed card that is valid thru XX/XX/XXXX. 
I consider the usage of the renewed card ending in XXXX ( valid thru XX/XX/XXXX ), in transaction XXXX, as unauthorized usage by PayPal. As the available balance on my PayPal account was not sufficient to cover the transaction amount in full, PayPal should have either declined the transaction, or prompted me to provide and authorize a payment method to be charged for the difference ( XXXX USD ). PayPal should not have charged the card ( ending in XXXX ) without my authorization under any conditions. 

I reached PayPal before the transaction got confirmed, but they told me that they can not reverse the transaction. 
On XX/XX/XXXX, I have contacted the issuing bank with request to reverse the transaction. 

I have tried several times to submit a complaint for the unauthorized usage of my card by using the form in their site, but after completing all the steps, I have not received any confirmation that the submission was successful. I also wrote them an email to address XXXX, but I received an automatic reply that my email will not be answered.