wanna know my right

All told, sounds like fine advice. If it was an honest mistake (which it sounds like it might have been, after all, they tried and even looked into upgrading it for you), I'd take the refund and move on. If it wasn't, it's fraud. In the latter case, a well thought out and respectful letter to the manufacturer explaining the situation and your lack of satisfaction could, at the least, cause the dealer some headache and, depending on the manufacturer, might prompt them to step up and lend a hand. Don't count on it, though. It may very well turn out to be an exercise in spite, however artfully sugar-coated, which is likely not worth the further aggravation. I wouldn't suggest pursuing any legal remedies, especially if they are willing to simply refund you money, as unwinding the deal and setting the parties back to their pre-deal state is a perfectly viable remedy in most courts of law (though, as folks were very correct to point out, under various contract theories -- not to mention fraud, fraudulent inducement, and the like -- you are technically entitled to more). I wouldn't let it taint the hollidays for you.

Let it go and have a happy holiday!

Take the refund, assume it was an honest mistake. It is very difficult to find a good hi-fi store. Sounds like they have been resonable. A friend at the local hi-fi shop is much better than an enemy.