I have tried everything to make google play store the default app store on my phone but its not working, I downloaded Fifa 2015 on google play store but the game won't play keeps asking me update it on xiaomi app store ..

Never used a Xiaomi device (have used the MIUI ROM though)
You can try freezing/disabling the Xiaomi store app with titanium backup. (You need root access)

Karmanaut:
Never used a Xiaomi device (have used the MIUI ROM though)
You can try freezing/disabling the Xiaomi store app with titanium backup. (You need root access)

i have tried all rooting app ..it wont root

franzis:
i have tried all rooting app ..it wont root

Device name? Search the XDA forum to see if there's a thread for your device.

Download the multi language ROM from XIAOMI.EU

That will remove all the Chinese in the phone and Google play will be the default store

Lemme know if you have any issue with that

debeo:
Download the multi language ROM from XIAOMI.EU

That will remove all the Chinese in the phone and Google play will be the default store

Lemme know if you have any issue with that

done but the Google play store keep asking for WiFi before downloading an app

franzis:
done but the Google play store keep asking for WiFi before downloading an app

If you are downloading from play store for the first time. After clicking download, it brings up the permission page, accept, the next button advises you to download through WiFi only (obviously to save data), uncheck the option

Alternatively go to downloads, click on the 3dots ...

Select settings,

Download size limit,

Change it from 'always wait for WLAN'

Change it to any download size you want

Attached are screen shots