[Q] Cannot update hike messenger on micromax knight a350 topic

I am having a problem updating Hike messenger app on my Micromax
Knight A350 device.
Whenever i try to update my app i get a error saying "Package file was
not signed correctly. Uninstall the previous copy of the app and try
again."
the problem is i can't uninstall the app as it is built-in i can only
disable it.
even i tried updating when it was disabled but no luck.Please can
anyone have any solution for this i emailed my problem to hike
support but no word from them yet. PLease help