(1) Survey being Duplicated Multiple Times

Have you contacted Support? They should be able to dig into what's going on if it's a Qualtrics issue (sounds like it may be).
If it's something you can address - it would be something around your settings:

1. Do you have incomplete responses set to record after a given amount of time? (like a month)? You can check the "progress" and "finished" status on those responses to see if they were actually finished or they were pushed to record after the date


2. If the person started the survey multiple times, instead of editing a previous started one...this also may occur with #1 above. You should be able to look at the IP Address for each...are they the same?

I spoke with Qualtrics support I guess it was an anonymous link that someone used multiple times however it still does not make sense as the information in the duplicates is exactly the same information

Depending on how you have your options set (do you allow multiple submissions?) then if I have an anonymous link, and I click it again, it will have all of my previous submission there. I can change it or just skip through to the end and hit submit. Voila! Duplicates.
If you don't allow multiple submissions, if I use the same computer/browser, it would say, "you already completed this survey." So to SPAM you then, I'd have to open the link in a new browser/computer and I would not have the data I used previously.