There are a few options. Our Customer Care Center is ready to help. Just call us at 877-387-4564. 

If you reach us after hours, email us the order number and we will do our best to accommodate your request (see also, How Do I Refuse a Shipment?).
​
If you're cancelling an Autoship order that hasn't shipped yet, then simply log-in to your account and cancel or postpone the Autoship date until such time as you're ready to start receiving shipments again.