Have Been Billed for Account I Thought Cancelled

About a month ago, as far as I was aware, I cancelled my Zoom Pro account because the reason I needed it had ended and also, I am now unemployed and need to manage my expenses VERY carefully. Today I received notice that I have been billed the full amount for one more year. The email is not one I can respond to - how do I reach someone to close the account and reverse the payment?