i have android 6 software in my phone,recently I was update my phone in android 7, before update android6 my phone 4g network voice call also going, but now after update phone in android7 ,4g voice call not going without data connection, volte simple not come in display in android7, what can I do for that problem , how to solve this problem in my phone, can I change any setting my phone , reply me.

thank you

Please first update to the latest Firmware and perform a factory reset in recovery after that.

wipe data/factory reset in recovery (this will delete your data/settings):
- Press Power and Volume up together for around 10 Seconds
- be sure that the little arrow point on recovery (select with volume up, enter with volume down)
- Then the open android with red triangle+"no command" is shown press Power and Volume up together again
- Select Wipe data/factory reset with volume keys, confirm with power
- After factory reset select reboot system now

Please report if this solved your issue or not. If not please tell us you current firmware version.