Well, we can sure try! (pictures being worth about 1,000 words). If you can name your trailer's year make and model, that helps, too.
FWIW, there's nothing really special about the remotes used in these systems, a universal remote can be used, though it will likely need to be programmed to work with your specific equipment.
Of course, you can also just google up "concertone remote" and see if you can find yours .. and a suitable retailer (or google "concertone" and see if you can identify the model number from the images provided, and then swim down to an appropriate remote).
has a few, as well.