How to cancel an active subscription without access to the account?

Fred20

Every year, an amount of €119.88 is debited from our account [removed as per Community Guidelines] with the reference [removed as per Community Guidelines] to the account [removed as per Community Guidelines]

We haven't used the subscription in question for a long time, but we don't have the login details to cancel it. Can somebody help us? 

We are a foundation that acquired the Dropbox mentioned in this email from another foundation, but we never received the login details. 
We want to cancel the account in question, but don't know how because we don't have any login details. 

Couldn't find any solutions in the F&Q in the Dropbox website.

Sincerely,
On behalf of the [removed as per Community Guidelines]
Chairman Fred 

Megan

Hey there, @Fred20, let's jump right into this! 

Have you tried to contact Dropbox Support directly for this?
If you open an incognito or private window, where you aren't logged into any Dropbox account, you can submit a ticket via this support page.
Once you've sent your request, feel free to send me the ticket number, in order for me to locate it on my end. Having said all that, if you come across an issue, I'll be more than happy to reach out to you instead.
Let me know more!