Hi SBilalZaidi,
Thank you for using Apple Support Communities. I understand you're having difficulties using FaceTime in Pakistan and UAE. I'd be happy to provide some insight.
I'd recommend taking a look at this resource: If you can't make a FaceTime call on your iPhone, iPad, or iPod touch
Specifically, this section:
"You might have issues using FaceTime for one of these reasons:
FaceTime and FaceTime audio calling might not be available for all countries, regions, or carriers.
FaceTime isn't available or might not appear on devices purchased in Saudi Arabia, Pakistan, and United Arab Emirates, including Dubai. However, with iOS 11.3 or later, FaceTime is available on iPhone, iPad, and iPod touch in Saudi Arabia. And with iOS 12.4 or later, FaceTime is available on iPhone, iPad, and iPod touch in Pakistan. Update your device to get FaceTime in Saudi Arabia and Pakistan. "
I'd also recommend taking a look at this resource: Find or restore a missing FaceTime app
Thanks.