May I ask if there are any outstanding or unpaid balance on your CF Account or even active and enabled service? 
May I ask if you’ve followed the instructions to disable and cancel your subscription for Pro plan as from below article?
Was it monthly or yearly subscription?
Was it lately renewed?
Upon the subscriptions are disabled, I believe you’re able to proceed to remove your CF account. Please, be aware it might disrupt your service(s) immediately.
Here are the steps:
Thank you for sharing your ticket number here with us.
The team is notified about your case and will respond accordingly onto it.
Questions about billing will need to be resolved by the Customer Support team and cannot be resolved on the Community.
Thank you for patience in advance.