Airtel — family plan does not work

Once you add a child number to family plan, the internet usage stops for the child. Escalated many times, but you always need 72hours more to resolve the issue and it goes on. So finally you need to remove the child.
I demand the refund of the 399 amount that was deducted while addition of the child. Also the advertisement should stop, if you can not provide proper service.
Complaint number 79440460.