I finally got my Wazapp working again after 3 days. As I was switching between my android phone, iPhone and N9, I got to the point when Wazapp kept saying "Fail-too-many" and persisted for the past 3 days. I emailed Whatsapp 7 times, asking them to unblock my account thinking that they must have blocked me from registering as I have tried registering for too many times using the same number, but they chose to ignore me.

Then i tried Whatsapp on my Android again today, I was able to verify and register. And I was still blocked on N9 and iPhone. So this brought me to think that some parameters must have been stored on the phone for the server to know that I have registered too many times. But problem is, i don't know where it is stored.

Uninstalling and reinstalling didn't help. So i clear device and re-install everything from scratch (not reflash), including Wazapp. And finally, i register my Wazapp on N9.

In case anyone got "Fail-too-many" without any timeframe indications. I am not saying that this will definitely work. Just sharing what has worked for me and hoping that this helps someone in the same plight.

Now a happy Wazapp user on N9. Thanks Tarek!