Not getting emails

After a purchase is made, we are trying to have an autoreponder email sent with tx info for donations but it is not working..what am I doing wrong?

The form you provided does not have an email field and because of that, you are not able to send the Autoresponder email to your users. The Recipient email inside of the Autoresponder settings has to be the email field. 

Setting up an Autoresponder Email

Explanation of Email Notification and Autoresponder Settings

Hope this helps to solve the issue.