If your subscription is in a paused status, you can resume that through your Alloy account page. Just log in, click "subscriptions" in the menu, then "resume" next to the subscription you'd like to begin receiving again. If you are due for an order, it will process immediately.
If your subscription is in a canceled status, you'll have to reach out to support for assistance. Just shoot us an email at support@myalloy.com.