I was charged $50 without notification/request...

I saw a charge of $50 from Avast that I had not authorized. I flagged the charge. The bank blocked my card. I have to get a new card. I checked my email for Avast and found they charged my account. I want to deactivate my charge. What do I do? I cannot see a phone number to call. Does anyone know how to call and talk to customer service?

https://support.avast.com/article/24/ (Orders/Renewals/Refunds)