The medical-imaging company Verista Imaging, Inc., may not be coming to Knoxville, almost a year after announcing it would move into the Old Farm & Home building to produce nuclear imaging cameras. Marion County Court documents report a contractor with Verista Imaging is seeking payments for unpaid labor, material and equipment costs. A separate filing issued a notice of foreclosure on the property mortgaged to Verista. Verista officials did not immediately return phone calls for comment.