My account was upgraded automatically without my approval.

My account was upgraded without my knowledge or approval. I have been charged the $99 fee despite having my account set as a free account. Please tell me how to proceed so that I can receive a refund.

I checked your account and it is subscribed to the Gold plan which is $99.00 per month. Please cancel your subscription on your PayPal account by following this guide: 

https://www.paypal.com/us/smarthelp/article/FAQ2058

After that, contact us again so we can request a refund. We'll wait for your reply. Thank you.

I did not upgrade my account to Gold. I have downgraded again already since
it was upgraded on it's own. I have also verified that it has been canceled
with Paypal.
...

I have sent a request to refund your payment of $99.00.  You should see that refund posted to your PayPal account within the next 7-10 business days.