Legal Question in Real Estate Law in California

Without seeing the contract there is no way to answer your question with any certainty. Basically, though, if you and he agreed there would be interest due, you still owe him. If you and he never agreed on interest and it's not in the contract he wrote up, he can't just add it now. As for how to get title, either he signs over the DMV paperwork to transfer it to you, or you take him to court over it.

Well, you've either paid everything you owe, or you haven't. This may be a problem that arises from a non-lawyer-drafted contract; it may lack clarity, may be unusual as to whenand/or how interest is to be paid, or maybe the seller/writer doesn't understand his own work. If the contract doesn't mention interest at all, I believe most courts would conclude that either no interest was to be paid, or that interest was included by implication in the size of the periodic payments or the purchase price itself. If you'd be willing to send me a copy of the contract by FAX or e-mail, I'll try to give you a more complete opinion,at no charge.