EB Games Ripoff Denyed me the benefits of a promotion contradicting their own add Miami Florida

The game store EB Games came up with a promotion which allowed their costumers to trade-in 3 games from three very specific gaming systems and be entitled to a $10 additional credit, the add also made sure to put in big letters that all games are accepted and there would be no exclusions as long as the games fit the qualifications. I went to the store on Friday 01-07-05 to buy some games, at the cashier the manager of the store told me I wouldn't be able to trade in the games for the mere fact that the games that I had just purchased too cheap, the games however, fit the qualifications of the promotion thus contradicting the add they're giving out at the store. I went there the next day, 01-08-05, to trade the games because i played them and did not like them, and also for the way I was teated the previous day at the store, and wanted to enjoy the benefits of the promotion. I was denied the right to trade in the games and receive the special which i was entitled for under the allegation that i had been told i wouldn't be able to do the trade-in the day before, even when the add provided by the store itself said:
"$10 Bonus Trade-in Credit, Receive an additional $10 trade-in credit when you trade-in 3 playstation 2, Xbox or game cube games.

All games are accepted. No exclusions!
offer valid: 1/02/05-1/30/04. Customer may be responsible for tax in some states. Game boxes and instructions required. Cannot be combined with any other offer or promotion.

Offer not valid at ebgames.com. Typographical errors not the responsibility of EB games. Dates of Promotion are subject to change.

As you may see, no restrictions whatsoever were made and the fact that I was denied the right to enjoy the benefits of this promotion make it false advertisement. I was very offended, and frustrated with the way they play with their custmers and I should very much like to know what can be done about that.
Thank you very much

Jose
miami, Florida
U.S.A.