If you do send to collections, you can have the agency initially send a letter. They'll probably charge you a few dollars for each letter whether you collect or not. You can also have the collections company call them as a next step. That's more work for them so they'll increase their cut. They'll probably want half of what they collect. You can also try and sell the debt or judgment to a collections company depending on where you are in the process. If you can find a buyer you're probably only talking pennies on the dollar.
Your billing company or system probably works with a collection agency. Try calling them and see which programs they have.
Or, as I mentioned above, you can pursue on your own through the courts, most likely small claims and try to get a judgment.