Cath, I have hornwort and anacharis in the pond now also, my pond is partially covered with ice. The fish are layering right now because it's cold. I have a plant that I trimmed and sunk to the bottom because it's a marginal and the fish like it to hide in too. I don't think you are doomed to lose your fish because you didn't winterize like you normally do. You can still trim and sink marginals as long as the water is open
(you probably don't wanna hear that, huh?) . There have been years when I don't get the marginals sunk either, didn't hurt the fish but it wasn't so good on the marginals...
It's been down in the teens here at night and my fish and plants look fine in the pond, but this is just the beginning. I don't have koi to worry about. Just remember to keep a hole open and some air to them and come spring they will probably be fine.
I don't think these companies are busy at all, but I think they let a lot of their staff go this time of year and are really shorthanded. Some of them may not even be open all week long or on the weekends.