1. Doesn't matter about who's responsible. Sure, it's their mistake. But shipping is just something YOU have to deal with. Yes, yes, they "should" pay for it but what Blake442 said is 100% correct. 99.9% of companies on the internet would do the same thing. Summit and Jegs are exceptions, they are well known and will go the "extra mile" so you might get different support from them.
2. $35? It's not a lot of money. I've been ripped off for a lot more. Suck it up. Work an extra 2 hours, really it's nothing. Not to sound harsh, but really, suck it up, it's nothing. You got a refund and that's a good thing.