I am so sorry this happened while you were working and you lost progress. I can understand how frustrating that would be and it's certainly not the experience we want you to be having.
If you could provide the following:
1) Browser you were working in.
2) Operating system/computer you work on (Windows, Mac).
3) The name of the survey.
4) How long were you actively working in the account before it happened?
If you want to e-mail us this information to social_support(at)constantcontact(dot)com along with your username and a reference to this post we can pass this to our upper level support team and investigate what is going on.