They switched batteries on me when i went just have my battery charged kept my good one and gave me back a bad one

My husband and I traded in our older model Cavalier to a newer model car. I was not really happy about the trade in value they gave us for our old car, but in the end, we did get a fair price for the newer car. The salesman that we worked with was very helpful in finding a financing option that would work well with our budget.