AutoNation Chevrolet Timonium

My 2023 Chevy Silverado Deisel had the service light come on for water in the fuel system. I took it to Auto Nation Chevrolet in Timonium Maryland. The vehicle was running fine and had no problems. The service Manager Jody called me and said that I should call my insurance company as they diagnosed that my fuel had DEF in it and that it would cost $35,000.00 to repair the vehicle. I went to the dealership and spoke with the shop manager George and the technician Tim they showed me a dark colored liquid that they said was my fuel and then they said they thought it had DEF in it but were not sure. I got on google and did some research and the dark color fuel was most likely contamination for bacterial or something called diesel bug. They still said it was most likely DEF in the system and said I should have the fuel tested (isn't that what they should do when they diagnose the issue)? I asked them about the $35,000.00 repair cost and they said they would have to replace the entire fuel system and injectors and it would take about 60 hours of work as they would have to remove body from the chassis. I immediately ran some quick numbers in my head 60 hours x $200 = $12,000.00. Now the parts would have to cost $23,000.00 and you can replace the motor and fuel system for less than that. I had the vehicle towed to another dealer and they did the repair with a diagnostic for $2,450.00. I contacted Auto Nation and found that they currently do not have a genral manager and then spoke to the sales manager Carmi and he said that he would have the service manager call me and I have never heard back from them. If this is how you treat people or potential customer's then I would close your business.