I hear ya, but I'm not sure what the question really is.
Did you read the HUD-1 before you signed it?
Do you mean that it's the wrong lender being paid off or the wrong figure or the wrong mortgage?
The title professional in charge of the transaction is obligated to correct any errors, but the mortgagor whose mortgage is being paid off has obligations, too. You have personal knowledge of your own business and so you must read documents and verify that the mortgage being paid on the HUD is correct.
If title insurance is being issued as part of the transaction, you likely signed an owner/seller affidavit in which you affirmed that you had reviewed the HUD-1 and that there were no mortgage obligations not being paid on the HUD. This document ties you to the HUD-1 and legally binds you to responsible review and correction as needed.
Mistakes do happen. Human beings make mistakes. People must watch each other's back to avoid mistakes. The owner/seller affidavit formalizes that concept and binds the owner/seller to the process of looking for errors on the HUD-1 before the transaction is completed.