BMW USA Corporate Office Headquarters

I leased a BMW 320i and it was advertised for $229/month approx. $4000 down. Arrived at dealership and asked about ad, told by salesman that even though $229 was in big blue numbers on side of car that it did not apply to Orr BMW, Shreveport, Louisiana. I proceed with transaction and later determined that it should have in fact applied to that dealership. I contacted dealership and was told that I "should have jumped up and down and screamed" in order to get the advertised deal. I filed complaint and Orr rep told investigator that that was NEVER the ad. They did not have $229 on side of the car. I know for a fact that my son and I both saw this. I am going to proceed with complaint(s) of any kind until I prove that I did not make this up. Do you have any suggestions? I simply want my approx. $4000 refunded and I'll give car back to Orr BMW – never to deal with them again