clarify selective sync backfill behaviours

Author: terence1988

src/connections/storage/warehouses/faq.md

@@ -9,7 +9,9 @@ Yes. Customers on Segment's [Business plan](https://segment.com/pricing) can cho
 
 Selective Sync helps manage the data Segment sends to each warehouse, allowing you to sync different sets of data from the same source to different warehouses.
 
-When you disable a source, collection or property, Segment no longer syncs data from that source. Segment won't delete any historical data from your warehouse. When you re-enable a source, Segment syncs all events since the last sync. This doesn't apply when a collection or property is re-enabled. Only new data generated after re-enabling a collection or property will sync to your warehouse.
+When you disable a source, Segment no longer syncs data from that source, and Segment won’t delete any historical data from your data warehouse. When you re-enable a source, Segment will sync all events since the last successful data warehouse sync automatically.
+
+When you disable a collection or a property, the automatic backfill behaviour doesn’t apply when that collection or property is re-enabled in the future. You will only find new data generated after re-enabling a collection or property synced into your warehouse. To recover the data, please submit a ticket to backfill the skipped data.
 
 You can also use the [Integration Object](/docs/guides/filtering-data/#filtering-with-the-integrations-object) to control whether or not data is sent to a specific warehouse.