Problem with Cancelled Subscriptions

When a user cancels their subscription in Spark, but are well within their grace period (they bought a month, cancelled a few days in) their "current_billing_plan" immediately becomes null. I see in the Database their subscription is still available but I'm not sure if I query the subscription model directly if I"m bypassing critical spark logic.

What is the correct method to determine a user's still existing, even if cancelled, subscription?