Yep, you're both right.
I spent 13 years in retail, and anyone who behaved as Tdukex described could have anything they wanted, especially if we had screwed up. I would only add that it helps if you dress well. ;-) Goodwill is worth a LOT in a competitive market.
Imagine the ripple effect if your posting had been about how GREAT the people at GC had treated you instead of the problems they'd caused. Everyone makes mistakes, but intentional deception is unacceptable.
I have a walk-away figure in my head that's gotten larger as I've gotten older. By staying positive and expecting good will, I save FAR more money in the long run. Sometimes, when someone has refused a smallish return, I just smile and say to the clerk, "OK, I won't be shopping here any more, and I don't like to carry around bad memories -- would you mind throwing this away for me?"
From a business management standpoint, your one posting here has already cost CG hundreds of dollars in business (probably much more) -- if I worked for them (anywhere, in any city, in any capacity), I'd be on this forum offering to make things right by you, just to get you back and to change readers' minds about how they do business.
There are two techniques that I recommend only as a last resort and when the amount at issue is over your walk-away limit.
Announce that either they will help you, or you feel you must return everything you've ever bought from them for a full refund so that you can start over with a different music store. Don't be defiant -- be sad and gentle -- after all, you're giving up on the relationship. It's a lot of work for you, and you realize it will be a big hassle for them. If they remind you of time limits on refunds, you say that unfortunately, then, the manager will have to contact corporate headquarters so that they can get your refunds approved before you return with a carload of merchandise, because once you show up with it, you have no intention of leaving the store until they've made it right by you one way or the other.
In the unlikely event that it comes to that, then have a friend accompany you with a camcorder. NEVER use any profanity or name-calling, and NEVER touch anyone, regardless of provocation. But feel free to speak in your best train-stopping stage voice, and express your concerns to all the customers walking through the door. Ask questions instead of making statements (e.g., "Why would anyone want to buy something from a store that has treated me so badly?" instead of "Don't shop here; they're jerks!").
If their store security is inexperienced enough to throw you out on your ear in front of the camera, well, you know where to go from there. When your attorney sends you your share of the settlement, spend it on equipment somewhere other than CG.
People like tdukex emit a vibe that only imbeciles and drunks can ignore. I get VERY nervous around someone who is calm about their claim, because they already know they are right. My best boss taught me the best lesson in retail: decide within the first second or two what you're willing to do, and then be as nice about it as you can. What's the point of making your customer defensive if you know already that you're going to give him a refund anyway? You might as well be so gracious about it that they remember the experience as surprisingly pleasant -- it costs the store the same whether you piss someone off or make them feel like they're the most important person you've dealt with all day.
Best wishes,
Mark H.