I had exactly this happen to me with one of my cats. I moved house, but only a 10 minute walk away from original property. One of my cats was not impressed and he kept returning to the old road. I constantly had to go back and find him and bring him home.
Then he found a single chap on the original road and he literally moved in with him. I did have the man's mobile number and he used to contact me whenever my cat needed to go to the vet - he was a bit of a scrapper.
I used to pick him up, get him sorted at the vet and take him back to my new house. He would have a meal, maybe hang around for a bit before disappearing back up the road to this chap's house!
My cat used to come home every month or couple of months just to visit. He would say hello, have a meal and then disappear off again. This went on for over 3 years. I just had to accept that my cat had made his decision about where he wanted to be although it was obviously upsetting. He didn't want to live in the new house with me and that was that. He was happy and well looked after so I just felt that I had to go along with this arrangement.
Then one day on the grapevine, I heard that the man had handed in his notice at his rental and was moving away. I had no idea what would happen next. He had assured me that he wouldn't take my cat, but I just didn't know what my cat would do in his absence. I was very worried about it.
The day came when the man was leaving and he sent me a text to say goodbye and he was just about to go. He was very sad at leaving my cat as he had really fallen in love with him, and obviously my cat loved him back.
Literally half an hour later, my cat strolled into my back door at the new house like he had never left! He just moved right back in after over 3 years like nothing had happened. I just could not believe it. He never left after that day and has been with me ever since. He is an old man now and has lived a very full life that is for sure.
So I would honestly say, please don't move away without your cat or at least find out where he is living and what the situation is. As my cat did this and one day moved back like he had never been gone.