If this is an image, select it and check your Links panel. There is a small arrow in the bottom left corner of the Links panel. Click this button to reveal the Link Info if you don't see it. Look for the Path entry which will show you where the image is located. You could either update or replace this image.
 Provide an InDesign document that contains the correct data and put that file to the data merge source file.
 Prepare InDesign formatted text instead of placing an InDesign page and let the data merge source file fill out the right contents. This would require a couple of new columns in the source file and a couple of corresponding data merge fields.