Decay of items

So, wondering if this has happened to any of you?  While I now know I should have been using secure containers instead of lock containers, but I was using lock down.  I released a chest and was putting stackable ingots into the container and within 2 minutes of releasing the chest it disappeared or decayed.  So asking for GM help which seems to be a joke, as all they can say is i'm sorry, tough luck. I was told well, different items have different decay times...ok what is the decay time for a chest?  Well the GM did not have a timer for everything...so I tested this and placed an empty chest not locked down and it lasted for an hour or more.  So can anyone at UO explain why a chest I'm putting items into decays in 2 min or less and a chest I do nothing with last an hour or more and then why can't you restore my lost items because I released them for less than the length of time of a standard horse race but another one last for over an hour?