Infor were responsible for our System 21 AS400 ERP for many years.
When I joined the company and learned my way around the AS400 it was very clear that it was "sellotape and elestic bands". We essentially had two ERP systems, an ancient one and a half install of its replacement. Both systems had been left talking to each other via triggers. It worked fine till it didnt, then you'd have to jump through hoops trying to convince Infor that they had to fix it as they were being paid monthly to do just that. Most of the time we were sent links to knowledge base articles telling us how to do Infors job for them, links that were not relevant because we were in a no mans land of an old ERP half upgraded to another now old ERP replacement.
Once the system went down due to a UPS shutdown. The system didn't come back up at all, on a bank holiday where I was the only IT support all day. Could I call them? Everything was dead. NO reports had been generated, the delivery note printers wernt printing and lorries were stacking up at all the sites phoning me asking why the printers arnt working and why the AS400 screen was blank. Infor had no clue why, even though they were experts on AS400 they had no clue. We spent a week having them manually triggering jobs on the AS400 just to have us get by, invoices, EDI, report generation all of which should have been automatic were now manual. Till our AS400 guru came back off holiday and discovered that the issue was the UPS shutdown program cleared the AS400's startup program value to have the AS400 start in a restricted state. So called AS400 experts like Infor, seeing a system that no longer starts correctly might have checked that the startup program was set.
Oh and there was the time where I had them on to fix something for a user. The guy killed the interactive subsystem. For anyone who dont know AS400, the interactive subsystem is basically a telnet server that allows ALL users access. If you kill it their screens literally go black and they are logged out with no access till its started again. Just what my boss needed, me coming into the cafeteria to pull him away from his lunch as the entire user base were locked out.
Infor also had all our custom source code, yes we had AS400 developers once and they created our own code to fix the system. When they all left Infor got the code and agreed that they would support it. Did they? Barely!
We eventually jumped ship.