Send them a snail mail with a SASE in it.
State that it's been a full year since you submitted (title) and you are inquiring about its status.
If they pass on it, then at least you'll know and you can query other houses or find an agent.
Hopefully you've been working on your next 2-3 novels since then and honing your craft. If they pass on your query & sample, you can polish both up for the next round.
On my first submission the publisher simply lost it. Considering the amount of material in the average slush pile ...
...that was understandable!
I sent it again, and they lost THAT one. The third query had the editor looking for its arrival--and that worked out. They bought it.
Of course it took a year's time to figure out what had happened. By the third effort of sending in the same material I'd gotten it nice and shiny polished, which might have had
something to do with it finally selling!
Good luck!