If you chill and get out of your rage, you will see I posted about how these things break down.
If his name was on the electric bill, should he have a right to turn it off if he went on a month vacation?
You can't control your room-mates, you need to pick them wisely.
This is a perfect example of this.
Now if that room mate was not in agreement to the internet service and the break down of bills shows only the OP is covering that cost entirely with no other shared bills being leveraged in kind.
Then he can do what he wants.
When I lived with a few people usually we'd break out the bills so it works out we were both paying an equal amount with the rent due being where the adjustments occured.
Just because my name is on a bill, doesn't mean my room mate couldn't have been.
Understand now?