Two Email Forms to populate DB fields correctly

My database script recognizes specific emails and automatically populates the first and lastname fields from those emails properly. Presently, this part works. However, when submitting an email form to download a product, the form gives and error message,"Your purchase is not in our database. Please make sure you picked the right item." This needs to be fixed. It should work as follows: when a user selects one and only one product to download, they fill in their first/last name and email address into the email form, then the first and last names match the first and last names that were populated into the database from the actual email and then the pdf automatically downloads. I also want to provide a form for users to enter their first name, last name, email address, and a varchar field for the user to input other email addresses for referrals. I want this information to insert into a new table called Customers that you can create on the db for my own use. Thank you!