Wife calling not working properly

I am using Nokia 5 (TA-1053)(India) sometimes it support the wi-fi calling and sometime not. I want a update to fix this issue, and want to use Wi-fi calling smoothly on my device. Please fix this. It's really helps me a lot. And i am a student, and I don't have money to buy new mobile. Please fix it, then I can use it. Please please please !!!