Hello Sushubh,this device is shit. i had to switch to load balancing feature myself because failover does not work well. in my case, it was not switching back to primary connection from secondary connection when primary connection came back online. as a result, it kept on consuming data from the second connection.
even on load balancer mode, it tends to not handle balancing properly if one of the connection goes down for a few seconds. as a result i end up with dead internet for a few seconds. but not as big of a problem as the one on failover setting.