Repairing small section of rust on the body

My F-body is in really good shape, save for the small spot behind the rear driver tire. There are two small rust holes there that I was looking into fixing. Apparently I'm very naive.

I went to a collision place and found they won't even touch rust anymore, only collision. Not only that, most places in my area are the same. Is there something I'm missing? Is there a black market for rust repair? What are my options?