What is the recourse when the buyer returns the item due to a defect after the price has been paid to the mortgagee?

Primary text

If the buyer returns the item due to a defect, he does not return against the mortgagee because the mortgagee rightfully received the price. Likewise, he does not return against the trustee because the trustee acted as a fiduciary and agent. Recourse is established against the mortgagor.