Improper use of your report: Vehicle loan or lease

I voluntary return the car and they said it was gone auction off for the full price but they didnt leaving me with a high balanced stew. I told him I am disabled. Im on Social Security now unable to pay that amount. They told me thats not my problem and then it showed up on my credit report. I said they told me they were gon na auction it off for close to what is old which is like $6000.00 or maybe less and they did not do that all calls or recorded. I hope they could pull it up. I called them and it said that they were not supposed to report that on my credit report and I just got the run-on.