Vivo x3s (Chinese phone) Google play doesn't open and no error

I had to flash the firmware cos the phone was stuck at the loading screen. When I bought the phone I just simply uploaded google play apk and installed it. Now it installs and when I tap on it it flashed for sec and nothing happens. I've tried cleaning cache resenting to the factory settings to no avail

Try uninstalling Play, restarting the phone, then installing a newly-downloaded copy. (And you also need Google Play Services installed.)