How do I make sure I don't end up on the bounce email list?

Just got a call from a customer of mine, wanting to know if I had looked at their quote request yet. I had no clue they had filled out the form, so I login here, and find 6 form submissions I never knew about because I somehow ended up on the bounce list. What causes this? How do I prevent it from happening again? Is there anyway to add a secondary email to my account, so if my primary email ends back up on the list, I will actually know about it, rather than losing potential customers. 

The email addresses will be added to the bounce list when our servers receive repeated bounce messages from the recipient email address due to any reason. You can remove the email addresses from the bounce by following the guide below:

https://www.jotform.com/help/262-How-to-Remove-Your-Email-Address-from-Bounce-List

Also, please check the following guide that can help you with troubleshooting email delivery issues.

http://www.jotform.com/help/208-How-to-setup-email-alerts-to-prevent-email-bouncing-related-issues 

Hope this information helps!