I can't see a full refund as mentioned on my existing Support ticket. Why?

jm311 wrote:

I found out that Dropbox had been taking money from my account using expired card details, without my consent or permission, or having provided them any new, valid payment details.

For future reference, that's not how most subscription services work.

In most cases when you have a recurring subscription and your card details have expired, your credit card company updates the subscription service provider with your new card details. This is called a card account updater and it's a service provided by your credit card company. The intent is to help maintain your subscriptions when your card details change.

Simply put, you can't just leave an expired credit card on file and expect that your subscribed services will stop due to a failed transaction. The service simply reaches through the credit card network and requests updated information. If your card company has updated information, the service receives it and continues to charge you to maintain your subscription.

Again, this is a service provided by the card companies, not Dropbox. If you don't want this happening with your cards, you need to opt out of the service with your card company.