Duplicate Line Items with submission and Google Sheets Integration

Often times a user will submit a form and it'll duplicate sometimes come through 10 times on multiple days. This is a real issue because they are ordering parts and often end up with more than they asked for. Is there something that an be done outside of unique submission since that is not possible. 

The user may have pressed the back button so this has triggered multiple submissions. If you do not wish to configure Multiple Submissions then you may configure the Uniques question. You may set this feature on Email field. In this way it will allow only one email to be submitted in the Form.

https://www.jotform.com/help/223-How-to-set-Form-Limits-Based-on-a-Unique-Question

Hoe this helps!

Thanks.