How to Warranty clam tinxy 6 node

I have 6 node model buy last 4 month but 1 node not working how to clam warranty

By sending us the device. Before that please call customer service 9319513343

Mene call kiya 7 8 baar but koi receive nhi kr rha

I m try call 7 to 8 times but anyone not receiving call , technical support is not good ,

when did you call ? what time ?