I have never in my entire life been so mistreated ...

I have never in my entire life been so mistreated and have had to deal with the unprofessionalism of this dealership. Salesman Jeremy Richardson and sales manager James "mj" Allen have been the most worst during this situation. My son bought a car 2 weeks ago, 3 days later the transmission began going out. They came up with a solution to switch cars for my son, during this ordeal, MJ presented us with cars available . 45 mins of waiting in the lobby for them to find the keys to the car "available", they come to us stating the car was sold this morning . But a Sentra was available, we test drive and decided to go ahead with the Sentra, they need documents from my son as far as pay and so forth, was told he was approved and for him to come in when he came back from his trip to sign. When my son came back , went to the dealership to sign, was told by MJ and Jeremy that he need a co signer bcuz even though his credit score is good, he just don't have enough credit. My response was that we was told he was approved last week. Well, it was a discrepancy and we didn't know this and that... so I'm furious bcuz everything was a fine deal last week!... now they are sending my son to delta community credit union to get a 6k dollar loan, after we was told that they would transfer the money paid for the car would go to the Sentra which was 5k$. And the Sentra was 7700 , so what would he need 6k loan, when I was ready to pay the remainder for the Sentra for him. Mj going back and forth with me in a very nasty way and in a nasty demeanor and said u know what, I'm not gonna go back and forth with a customer, I told him my husband wanted to consult with a lawyer, he states well since u threatening then u can just go ahead and take ur car to get transmission fixed. My son had only had the car for 3 days and they refuse to help us. My son worked and saved up all his money to buy a dependable car due to the fact that he wanted something reliable bcuz we do not have family here so he didn't want an unreliable car to break down on him bcuz he would have anyone to help him if he is on side of the road! We were basically dismissed in a very very very nasty way. They didn't even want to tell us what was really wrong with the car when they put it in the service area, they kept beating around the bush on that, they knew it was no good. Then they won't even tell us the cash price for the Sentra ... he just kept telling me 6,000 out the door.. I'm not sure if it's 6k total or an additional 6k with whatever that was going to be switched over from the first car into the Sentra... up til now I don't have a cash price. Never in my life have I dealt with something like this and I'm completely shocked that it would be from a huge dealership such as Toyota... will never ever deal with them nor refer anyone to buy there ....BEWARE, KEEP YOUR MONEY AND GO SOMEPLACE ELSE!