Asus India — 4g 3g not working after update

4g is stopped working after updating to latest firmware.

I called my network provider, check my sim and network and have no problem. They said 100% is your phone have problem.
Suggested me to put my sim card to other phone then its work, pick up 4g straight away. I put my other sim card to my asus phone and won't work and won't pick up 4g.
I am having the same problem since the last october 2018 update. I emailed asus and they said they weren't aware of a problem. I sent screenshots, they can't fix it. I will have no option to stop using asus products in the future.

Please resolve the problem quick