need some more info. Did you pay off a judgment that was clouding title on the property and now the judgment holder won't give you a "paid in full" letter and says the judgment was sold ?
If that's the case where is the evidence of the paid judgment ? Like a cancelled check, certified mail receipt showing confirmation,etc. ?
If you have proof of payment yet the debt is not settled you can slam them hard. There is a lot you can do to squash a crooked creditor that claims they were never paid.
You might have go after them but a nasty gram with proof of payment and letting them know you will take everything they own for trying to swindle and defraud you is a good start.
hope that helps.