Sounds like you'll be made whole. Some of those ads on gunbroker have more disclaimers than info on the item.
It's very frustrating when you've been after a specific item, think you've found that item, then it turns out you haven't. Glad you got your purchase price back at least.
I've purchased a number of things from gunbroker over the last couple years. It's completely hit or miss. I've found great deals there on firearms/ammo with free shipping and no credit card fees, and I've also been charged 3% extra and $30 shipping (USPS) for a scope - neither of which were mentioned in the listing. Most sellers don't seem to use gunbroker's check-out feature - frustrating because the check-out feature is pretty handy and fairly well-designed when you are purchasing a firearm.
I already did that about shipping.. the guy called me today and explained what happened. As I suspected he sold the one I bid on some time ago, listed another one and didn't upload new pics. He agreed to pay all the shipping costs and offered me all manner of means to make it up. He said he knew of a couple more locally of this rifle and would look into it. Not going to hold my breath on that, told him just refund my money and shipping. We shall see...