So my parents got convinced to move from old copper landline to a wireless mobile router that they can plug their phone into. Spark is trying to get plain old landline users off the copper network. Was working ok, but....

Today I tried calling from my 'landline' number. I just heard music playing. No ringing sound at all. Figured maybe the new system had some sort of call waiting thing so hung up.
Tried calling half an hour later - same thing.
Called from my mobile - went straight to voicemail.
Tried an hour or so later from landline - no ringing sound, but parents answered. Said it had been making a different ringing sound lately but they thought it was working ok.
I suggested they reboot the wifi router thing. Tried calling them again from my landline - again no ringing tone, just music played in my ear, but parents hear phone ringing and picked up.

Suggested they call spark.

Anyone got any ideas?