do you sill need filters when efibre socket is installed??

A friend has efibre from VF and recently it kept going off, a solution was to unplug a phone extension and so far it seems to have worked. But they have had efibre for a few months so why the fault now? speed is 70mb down. I was wondering do you still need those filters with a phone that is not connected to the new type socket? Or is it a wonky router? They have 3 extensions but dont know about filters.