The documentation says:
ReceivingEnabled If set to 1 (OFF) no messages will be received. If set to 2 (FOREGROUND) or 3 (ALWAYS) the component will respond to messages if it is running. In the case of 2 (FOREGROUND), messages received while the app is not running are discarded. In the case of 3 (ALWAYS), messages receive while the app is not running will show a notification. Selecting the notification will bring up the app and signal the MessageReceived event. Messages received when the app is dormant will be queued, and so several MessageReceived events might appear when the app awakens. As an app developer, it would be a good idea to give your users control over this property, so they can make their phones ignore text messages when your app is installed.
The problem of not receiving all texts could be an issue related to your cell provider, your Android version etc. New Androids might get fussy with this feature as Google tightens security protocols and might not work in the background with some Android phones.
What version of Android are you using Jose? You might try a different phone and make sure you set ReceivingEnabled to Always (#3)