cancel all paid subscriptions

Try here: https://helpx.adobe.com/document-cloud/kb/cancel-subscription-acrobat-online-services.html

If it doesn't work contact Adobe.

Hi

We can't help with billing. Contact Adobe Customer Care:
https://helpx.adobe.com/contact.html
Click the chat icon in the lower right and type "agent".

Note that there is a cancellation fee if you are cancelling before your contract expires: 

https://www.adobe.com/legal/subscription-terms.html

~ Jane