What kind of server do you use to push the notification? I think the main problem isin your server side I am the individual professional developer in Android platform, and have more than 5 years experience on this platform. I did many projects such as Barcode Scanner,certificate management, GPS tracker, Customized Lock Screen, Social App(integrated email/facebook/twitter) and fancy ToolBar etc.
And the delivery time and price are negotiable.
Thanks!
Alpha