Was this an intel board (LGA)? It's VERY rare to get a board with bent pins right out of the box since they have that cover on them to prevent it.
I'm assuming you're just getting into building PCs and had a learning opportunity given to you. We all mess up, some less than others. That being said, you can be ethical and just tell them you bent the pins and hope they take some pity on you; it is Christmas.
If you decide to play dumb and tell them it won't boot they may take a look at the pins. It's also possible they may be so burnt out they just want to get done with their holiday shift with as little work as possible.
Whichever you choose, don't be a dick. That poor person behind the counter has been taking shit all day long from angry customers. After standing on your feet for 8 hours for the fifth day in a row, you'd be burnt out yourself. Be as nice as possible and they may decide to reward you for not being a bile spewing cock monger. (Sorry, worked many holidays seasons in retail.)