don't use killall.
for start at bootup/run in background you need to use either services or init.d if services is not available
so use
sudo service tvheadend [start/stop]
or
sudo /etc/init.d/tvheadend [start/stop]
if you cannot login you need to edit /etc/default/tvheadend and change
TVH_ARGS=""
to:
TVH_ARGS="-C"
PLEASE NOTE THIS WILL MAKE YOUR TVHEADEND OPEN TO ANYONE TO ACCESS SO KEEP THE MACHINE CLOSED TO THE INTERNET OR SETUP ACCESS ENTRIES STRAIGHT AWAY AND THEN REVERSE YOUR CHANGE.
as for free IPTV channels i'd love some too. if you do find any let us know on here, but I don't think any exist.