I can't find any logical explanation of the key point that makes all of the Futurama series run, at least in the episodes I've seen.
I guess that at least Fry's family reported his disappearance to the police once he didn't return that night from his job.
Once done, the most logical thing that would have happened would be the police going to Mr Pannuci's shop where they would have been told that Fry hadn't returned from his delivery to the cryogenics lab. The police would have gone there to search for clues, they would have found him, they would have opened the cryogenics tube and well... none of Futurama would have happened.
But even worse than that is... does no employee in the cryogenics lab realize that there's a person in a tube who on the previous day wasn't in the lab, and they don't even have the slightest idea of who he is?
Maybe Nibbler somehow managed to bribe the police or the employees or used some memory manipulation technique so people wouldn't care about that, but I haven't seen evidence for that.
So, how was his forced cryogenization not discovered?