Help Mobile is not showing call screen both on incoming & outgoing calls and even not ringing?

[pranavindia]

My mobile is rooted. After rooting it was running smooth for few days. I have uninstalled few system apps (I don't remember which apps) but I haven't uninstalled any system app related to dialer. But phone is not showing call screen on calls and moreover, it is not ringing on incoming calls. Only thing I'm getting is a missed call notification after call. I even did a factory reset to phone but still the problem exists.

I really need help! Please!

 

[Dannydet]

Have you tried installing other dialers?

 

[pranavindia]

Have you tried installing other dialers?

Yes. Though that another dialer app has its own caller screen but it is not showing up every time and phone is still not ringing.

 

[mikedt]

Quite frankly it does sound like you deleted something you shouldn't have in system, and you'll need to reflash the original firmware. As it's an Oppo, can you read Chinese?

 

[pranavindia]

Quite frankly it does sound like you deleted something you shouldn't have in system, and you'll need to reflash the original firmware. As it's an Oppo, can you read Chinese?

No, I don't understand Chinese.
Can I download latest Oppo update from Oppo website and install it as local update from settings? Will it fix the problem?