The only good thing about filing a complaint with [BBB] is that others will be able to view the amount of complaints the business has on file.
Umm...that's the whole premise of the BBB. Its not a law enforcement agency, they can't go in with guns and force the offending merchant to exchange the product or give your money back.
The only power BBB has is to sully the BBB record of merchants when they fail to make an effort to resolve credible complaints. There is no conflict of interest because merchants pay a membership fee to the BBB. Look at the number of companies with unsatisfactory business records at your local BBB, apparently they aren't getting their money's worth.
That said, a former co-worker had this happen to him at Best Buy or Circuit City, I forget which. Except it was a color television. He got it home, opened the box, which appeared never opened, and inside was a dusty 10 year-old television. They didn't believe him when he brought it back. After he insisted on speaking to the manager, then his boss at the regional level, they asked him to leave or they would call the police. I'm not sure what eventually happened, if his credit card company approved a charge back or what.
The thing is, I doubt I would believe him either, if I didn't know him. Dishonest people try to pull return/exchange scams all the time.