If you have previously cancelled your subscription, but have received notice that you have a package being prepared for you, that is probably because you cancelled after the payment was processed. Cancelling your subscription will not affect any outstanding orders.
Payments for the current month's delivery are processed on the 5th of the month. For example, the payment for the November beers is processed on November 5th. If you cancel on or after November 5th, you will still receive your November package. You will not be billed for further packages.