Before you can edit a survey that you don't own (haven't created yourself) in Qualtrics, two things must happen, in this order:
If the owner of the survey added you as a collaborator before you logged in to Qualtrics at least once, the owner of the survey needs to remove you from the collaboration screen so that the survey is NOT shared with you. Then, the owner of the survey can add you again as a collaborator, being sure to select you from the directory menu.
Check with the survey owner that you have been added as a collaborator with permissions enabled. If the owner of the survey is no longer at Tufts, contact it@tufts.edu to change survey ownership.
If you cannot resolve the issue based on the above steps, contact Qualtrics support by following these steps: