I had the same issues.
I simply used a zwave wallplug for the modem.
ping sensor app for my vera
a trigger and a schedule, the trigger on the ping sensor , when 8.8.8.8 can not be pinged for so many times , to switch the wallplug off and 10 seconds later on agan.
also in the scene the switch the wallplug om every hour ...... just in case the after 10 seconds on didn't get trhough.
that works quite well now for over a year.
Cor