@Are you joking wrote:
I have been charged for an account I do not have
Use the credit card charge lookup tool to identify the account you're being charged for. If it's not one of yours, contact Support.
Visit the Support page while you're NOT signed in to a Dropbox account, including these forums, and you'll see an option for Billing issues. It's best to use an Incognito or Private browsing session to make sure you're not signed in.
Dropbox cannot charge you if they don't have your billing information. If you've been charged and didn't give them your billing information, then someone else has and you should be contacting your bank.
