weird laptop

this is weird, i have a customer with a new asus laptop. connection to internet,know porblem. But they take it home and can only connect using the battery.!!! Using the power main somehow cuts out the internet. !? Checked power supply and phone via local phone people.
I have not yet visited to look myself -
anyone come across this please
tks

Try it with a different power supply.

Sounds like something you definitely need to make an onsite visit to troubleshoot. It may be something as simple as they are unplugging the phone connection for some reason when plugging the battery in.