Commercial freezer stops cooling and goes into delay start mode.

The freezer does eventually cool, but not consistently or quickly. Our Jimex/Coldtech J2SFF-21B freezer starts, when we plug it in, with the cooling light on the temperature controller (model SF-104) blinking, which the manual says means it is in 'delay start mode.' It doesn't cool during this time, though the inside fans run. After a few minutes, it switches into cooling mode, and I can hear the unit turn on. But 5-30 seconds later, the display blinks and beeps and switches back into delay start mode. Over hours, sometimes the unit will inch down in degrees, but at other times it seems not to cool at all. I've left it on overnight and found it freezing in the morning, but haven't been able to catch it actually getting there. Unfortunately, for what we're doing, we need the unit to cool somewhat quickly and predictably. Extra unfortunately, the company that made it recently went out of business and even though I have manuals and they provided a partial list of recommended replacement parts, I can't actually talk to them, At first, I thought this was a programming issue, and tried checking all the parameters and changing some of them, like 'compressor start delay,' 'hysteresis/differential,' and 'offset for the evaporator temp reading,' and also played around with minimizing the defrost to make sure that wasn't an issue (it's not indicating that it's turning on). But the pattern stays basically the same. Now I wonder if there's something kind of shorting out whenever the unit cools for a few seconds, and then the whole program starts at the beginning as though it's just been unplugged and plugged in. I'm not familiar with that part of how the freezer works, and I'm not sure how it would go from that to eventually freezing. In addition to the temperature controller, there's a button panel with things like 'refrigerator on/off,' but it seems to be not intended for the owner to mess with (it's covered by the panel), isn't even mentioned in the manual, and in any case does nothing I can notice if I do push the buttons. Has anyone seen anything like this and have a suggestion for us, or even the name of the part(s) of a freezer that might be involved in something like this so I could do some more research? Thanks so much for your time in helping out and all the best! Melissa