My 3rd graders got a collection letter....what will happen???

Can you believe? A dentist’s office continually incorrectly submits our claims to my insurance. I go over it every three months with them, and thought I had it straightened out – nothing to pay. Well instead of sending me a bill since the last time I called (December) a collection agency is trying to get money from my 8 year old. I’m so tired of trying to straighten it out, have them resubmit under the correct ID, etc. etc., that I just want to ignore it. How long will this nuisance stay around, and can it have any effect on her financial health later on? She is 8. I can’t believe these morons sent this to collection without notifying the responsible party? I wrote to the collection agency to dispute the charge, is there anywhere I can turn to?