Lines Automatically Camp on and off

[Teleco4321]

I am having an issue with a customer who has and SL1100 system that will automatically camp on a line at random times, at least once a day and sometimes on all 3 lines. We cannot turn off the feature it will just turn off whenever and its been up to 2 hours stuck that way. I have turned off the Camp on in the system and we have tried using the code to disable the feature and nothing works. the system is at the latest release.