I am having problems with a Belkin N150 F6D4230-4 v2

Previously replaced a faulty Thomson Wireless modem. Had issues with the first N150 so returned it. Now I am having issues with the second one, if the line connections (Telecom) goes down from time to time, it not only kills the internet (which is expected) but it also kills any wifi connectivity, but also any cable connectivity to the router. To resolve I need to restart the mobem router

I have done a test where as I have not plugged in the phone line to the modem router, never had any issues losing connection to the modem router. When I plug the phone line in and connection is dropped via phone line, it kills the Lan connection.

I would have thought that if the internet connection goes down I would still have lan connection either by wifi or cable.

Can be a real pain cause I have NAS so makes it hard to transfer data. (they are working on replacing or upgrading the cabinets in our area so having a few internet connectivity issues

Anyone had these issues and know a way aroud it?