National Auto Sales, Marietta, GA DO NOT BUY FROM THEM, THEY DO NOT STAND BEHIND THEIR CARS Marietta, Georgia

I have had problems with my 2003 Rav4 Toyota every since I purchased in March 2012.  It has been back to their shop on 4 occasions.  The check engine light came on about 3 weeks after purchasing and the their service center said that it was the Thermostat. 

They Supposedly fixed it and when I picked it up,  the light came back on the next day.  Well when I called them about it,  Mark in the Service Department stated that it was nothing to worry about,  to bring it in when I got a chance. 

Once I took it in this time,  they stated that it was the O2 sensor,  I had to pay for it this time.  Well once again,  after picking it up a couple of days later,  this check engine light came on again.  This time it was they say because the mechanical had put the wrong O2 sensor on the vehicle. 

On Monday August 6th while on my way to work,  all of the sudden my vehicle would pick up speed,  the battery light kept blinking on and off.  Once I got to work,  the vehicle shut all the way done.  Meanwhile,  I am very upset because I havent had this vehicle long enough for it to have brokened down 4 times.  This time they said it was the Alternator,  and it would be $400 for me to pay.  I refuse to keep paying money to have the vehicle fixed when they knew it was a lemon in the 1st place and that is probably why I did not receive a Car Fax.   I will be contact Jim Strickland and Clark Howard in reference to this.  I turned the vehicle back in on yesterday and I don't feel that I should be responsible for anything.  In fact, I feel I should be reimbursement for the payments that I have made and my down payment.