Power sockets ARE one of the easier things to replace so in that sense, you are lucky. But, If you try to fix it and there are other problems, then the seller will be able to say that you screwed it up and make the whole process much harder for you to get your money back. I'd go for refund and start the process NOW!
I'd be worried that if one thing was visibly broken their might be more unseen damage. It is obvious that the seller did not represent the item properly in his auction (This is sketchy even for "AS IS") so I would bet he isn't an honest person.
Do you still have the link to the auction? Please post it here so we can:
A) See how he tried to represent the board so we can offer pointers on how to present your argument.
B) So others can know who the seller is and be more cautious around his sales.
Which ever path you choose to do, GOOD LUCK!
