I am having trouble with the delivery of forms

When we receive a form from our website,  we get two copies on more occasions than not. 

When trying to reply to the form,  quite often it comes back to me as undeliverable, as when you use the reply button provided, it goes back to jotform.   

If I understood you correctly, you are not receiving email Notifications when your form is submitted. 

I have inspected form you provided and I saw that you have two email Notifications and one Autoresponder email set inside of that form. However you did not set Sender email on non of them. 

You need to set sender E-mail. I would suggest you to set Sender E-mail to noreply@jotform.com. 

Inside of this guide you can find how to set Email Notification and Autoresponder: 

http://www.jotform.com/help/25-Setting-Up-Email-Notifications 

http://www.jotform.com/help/26-Creating-a-Form-Autoresponder 

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

Reply-To Email: Should be the persons email who fills out your form. It is attached to your email field from your form.

Also please check this guide: http://www.jotform.com/help/30-Notification-Autoresponder-Email-Details 

Hope this will help. Let us know if you need further assistance.