Nothing you can do - best option is to suck it up and just pay for it yourself.
You'd have next to no chance of success through the small claims court. Even if you did, it's almost impossible to make them pay. I also doubt any judge would award you a full refund given the cost to remedy is relatively minor, by the time you tried to enforce the debt through a third party agency, you'd only be slightly better off than you are now... that would all rely on actually getting a favourable judgement.
One of the risks of a private sale/purchase.