your company is very difficult to deal with. #15761164400. Please refund! Didn't request this product.
First I'm an avast user not an employee, so I can't speak for avast.
At some point you must have, otherwise how would they get your payment details ?
Did you sign up to the trial version which would require your payment details, payment would be taken on completion of the trial period or you would have to terminate the the order/payment instruction.
If you had an avast paid version previously, with an auto renewal subscription that would kick in at renewal time.