Car Dealer lost my letter

I rec'd a mail direct for special deal on Memorial weekend car sale. The letter stated all the 'come on', and 'plus you may have already won $4,900 cash if the number on your letter matched what posted in our show room'.
In the market for a truck, I went in with my letter un scratch (the silver spot with the magic number). The saleman collected my letter. When I repeatedly asking for my letter, they told me they couldn't find my letter.

I left with my purchased truck, was told to call the next day for an appointment with the General Manager to discuss the issue.

After several phone called, the Sale manager told me they have requested an identical copy of my letter and will let me know when they received. While on the phone with the Sale Manager, the saleman called on my other line saying they got the copy of my letter and I did not win. He faxed it to me.

Un satisfy with the answer, I went in and spoke to the GM face to face. They showed me the 'copy' of my letter. The GM assured me that the letter is an 'authentic' copy of mine and that he can get the company who handle the marketing to attest to that. I agreed to hear from the Company. He said the process will take several days. I left with a photo copy (made from a copy machine in the show room) of my 'copy' letter.

The next day the Saleman called and said they found my 'original' letter. I came in, the letter looks like the 'authentic copy'. Someone has scratched off the silver spot. When I asked to see the 'authentic copy' and the 'original' side by side, they couldn't provided to me. This time the saleman let me have my 'original' and kept a photo copy for himself.

I like to think as a big Dealer, they don't risk their business to do anything illegal but the way things happened to me seem very 'questionable'. Who can I contact to look into this? Or should I just let it goes?

My apology for a long question.

Thanks

[annjd]

It may hard to prove what they did now after you left?

Could you show if they defrauded you somehow? Not clear to me how you would do that based on what you said here?

The silver spot on my letter when they got it have not been scratched.

The way they handled the whole thing is very odd.

When they can't find my letter, they said it may have been shreded. There was no answer (that makes sense) to my question: why?

The GM said he will get the company to send the letter to attest that the 'copy' was my orginal. They (the company) had the list of who has what number to verify the winner.
Then the next day the Saleman said we found your original so there is no need for the company to attest.

If there is nothing to hide, and if indeed my original letter found, why the silver spot scratched. Shouldn't they presented it to me and let me scratch it off?

I did some research on my own. According to some of the companies that handle mail direct (as with this case), they do not know who is the winner. An identical copy (with the same number) can not be re produced. They can, however, print my name, address on another letter and consider that a copy.

The Car Dealer refused to give me the Company who handles the promotion.

I have to leave because it was 8:30pm; they are closing the door.

Thanks