When the mortgage was sold to the other company, the original lien was transferred. My first mortgage company was a small company, who then sold it to Wells Fargo. When it was transferred a transfer notice was sent to the county to tell them of the new lien holder, and I got a copy of that letter.
When I refinanced a few months ago, the Wells Fargo lien was released, and a new lien was filed for the new mortgage.
I smell something rotten going on, like maybe the lien wasn't transferred when they bought your mortgage. If the original company ceased to exist, and that was the only claim against your property then there was effectively no lien holder. At some point the holdings of that original company was transferred to the new company, and they should have filed the paperwork to show they now held a mortgage and a lien against your property...
I am no mortgage banker or anything, but I have bought and sold a few houses and dealt with my mortgage being sold a couple times. Its common, and its routine if done correctly.