Conclusion
It is important to be clear about your system vendor's role in the maintenance process in order to avoid finger-pointing. For example, imagine that your system is down. Upon calling the system vendor and describing your situation, you are told that the problem is with your internet service provider(translation: call someone else). But the ISP says that the problem is with the system software, so around it goes. Your contract must contain language that specifically defines the system vendor's responsibility for maintaining operations once the system is installed.