That is exactly why I cannot port my primary SIM to Afrihost. It works fine as a second SIM or for data-only purposes, but their lead times are ridiculously long to deliver a physical SIM. The 4 that we purchased averaged a delivery time of almost 2 weeks!
Depending on your router, you can also monitor uptime via the LAN/WiFi connection. Some TVs (I have tested with LG AND Google TV) have integrations to directly monitor and control the TV.
If the TV is connected to eg a Google TV box or a sound bar using CEC, then switching that device off will...