Firmware update major problem

I bought a Chinese ZenFone 2 off eBay and have had problems with most apps constantly asking for permission so I tried to update the firmware but it kept erroring so have checked what firmware I have and on the recovery screen it says cn but on the update page it says ww so I can not update the firmware have done a full hard reset twice and it's made no difference I really like this phone but the problems I am having are driving me mad, I just want to have apps that just work I'm not that technical and don't want to break my phone so can anyone help me