app uninstalled webhook not firing by Fahim Durrani

I've created a webhook, everything looks fine. but the event is not firing and i'm not getting any request from shopify when i uninstall the app.

This is the response i get when i create a webhook

{"webhook":{"address":"http:\/\/{mydomainhere}.com\/shopify\/webhook\/uninstalled","created_at":"2015-07-10T15:43:14-04:00","fields":[],"format":"json","id":25979653,"metafield_namespaces":[],"topic":"app\/uninstalled","updated_at":"2015-07-10T15:43:14-04:00"}}

Can somebody tell what am i missing?