Should they be responsible: Yes

If I were in your situation I would call the person in charge and talk to them about this. Tell them you have sent numerous emails and nothing is being done. Tell them you think they should be responsible for part of this bill.

If they say no, there isnt all that much you can do. You could bring them to small claims court, but I doubt that it would be worth your while.

Most of these companies are non-profit, and you can't squeeze a rock.