I would encourage you to put together a story that illustrates the pain being caused by this software and get with the purchasers. Not only might it help your organization figure out they need to do something different it could also show off your skills to the orgainization.
Could you collect the time you and other people are spending working on these problems? How many issues are reported to you? How many bugs you've filed and have not had fixed by the vendor? Rolling this up into a real dollar coast it's having on you and the school district users.