Distortion during calls on 4G Network unable to hear caller’s voice

When i make calls, all i can hear is distortion during call, But caller can hear me properly when i plug in headphones or turn the speaker on, it still doesnt make any improvemen. but facetime, what’s app call, i hear voice without any distortion. But if I disabled the mobile data then and then make any voice call then there is no any distortion in hearing. Please help? iphone 5s and using AIRTEL 4G network.

Solution which work for me- Disable the mobile data and then make any call and I found the distortion is all gone but all the time I need to disable the mobile data before receiving or making any call.