Bad Service with Misrepresentation

We were interested in a pre-used vehicle and contacted Lyndhurst Auto to get an approximate trade in value for our vehicle before we went to see the vehicle advertised at Lyndhurst Auto (Our vehicle sells for around 90-100k). We were told it should be between 65-70k. We then took our vehicle to Lyndhurst Auto where they took photo's and added it onto their \Bid Trade"site where other dealerships could bid on our vehicle. At first we were offered 16k for our vehicle! We were told that this is because the service history had not been added yet and we should get atleast 50k when the service history was added. We were then phoned and told that they would only give us 23k for our vehicle! How absolutely disgusting"