Can I get my money back or stop paying more than the value of my RV?
You can sue the owner of the RV for fraud.  Fraud is the intentional misrepresentation of a material fact made with knowledge of its falsity and with the intent to induce your reliance upon which you justifiably relied to your detriment.In other words, you would not have purchased the RV had you known its true condition.You can stop making payments and sue for fraud to recover what you already paid (your out-of-pocket loss).  You can also seek punitive damages in your lawsuit for fraud.  Punitive damages are a substantial amount to punish the intentional wrongful act (fraud) perpetrated by the seller.