auto generated submission

Dear Sir/ Madam, 

I received 10+ auto-generated submission from my clients without his knowledge (as per attached), could you help to check whats' the problem and how to fix it? My username is mypgsts.

Thank you.

Hello,

It's possible that he had the thank you page of his last submission open in one of the tabs on his browser. So everytime he closes the browser and opens it, it requests to make a submission. 

To prevent this, you can try enabling your unique submissions option on your form and set the restriction to check cookies only. You can refer to this user guide to learn how to set this option: 
https://www.jotform.com/help/64-How-to-Set-Unique-Submissions-on-a-Form

If you have questions, please do let us know.

Thanks.