They went behind my back and did a loan without my...

They went behind my back and did a loan without my consent. Even though I gave him a dealer letter from my bank. After purchasing the car I realized it was higher rate. So not only did they lie to me, they did another loan behind without my permission. After confronting the salesmen on via text message he decides to disagree with me. Also blames my bank claiming that they changed the loan. After arriving to driver select and asking for return policy the manager says they don t have one. Also does the same thing and blames the bank. After calling my bank they said that they never used the code for my loan and did a completely different loan.