Where do I find my abandoned 401K in retirement plan after a company has been sold

Due to being ignorant and not understanding what a 401k was or about. I was told. It would be wise to invest. So I invested 6 years in the top tier and the lowest tier. Unfortunately I had to quit my job.
nevertheless I was told to leave my investments in the company and as long as I didn't withdraw that my money would grow in my account and it would be my nest egg.
Now that I am disabled and no longer able to work I need that nest egg. Unfortunately the company was sold and my investments were so long ago ..15 years ago that the company no longer have information about my savings. And due to this large company being based out of Canada. I am trying to work with State and city and banks but I am being told that it's so old that it's been archived and I'm getting nowhere. This has been going on now for 2 years. Now I'm homeless. Living out of my Brock down car and very flabbergasted due to this situation. Please help.