Whatsapp problems with windows phone 7.8

[Windows Central Question]

I am having a problem while installing whatsapp. I had to uninstall whatsapp from my phone since it had expired and i was having problems with windows marketplace. I reinstalled it and it says 'Cant register with this phone number. You can only register with the phone number that was last used with whatsapp on this phone'. I havent changed my phone and the number. I am using nokia lumia 710 with windows phone 7.8. I formatted my device and installed whatsapp many times but the error persists.

 

[The Extreme G]

https://www.whatsapp.com/faq/en/wp/21478428