Multiple emails still being sent using Universal Email

My client uses Gmail as their email provider. I have a form that is filled out by a potential customer, the form is submitted to another page that 1.) Inserts the form data into a mySQL table. 2.) Runs a query based on the form info and returns pricing to the client on screen and 3.) Sends a copy of the pricing information to the customer and CC's to us.

The problem is that emails keep getting re-sent, it may be the next day, it may be two days later but emails will be resent sometimes multiple times. I believe this is an issue with the email provider as I don't think UE could resend the another email the next day. Google is the email recipient for my client and they have been little help. Can someone please take a look at my code and let me know if I have something wrong, this has been major brain damage.