Ajax form submission?

Question

PHP

Hello!
Such a problem:
There is a list of products, in the data-name I pass the name of the product

When clicking on this button, a form opens, it has fields to fill in and one field cannot be edited, I immediately pass this name there with the data attribute


The problem is that when I I process the form (ajax), then only the full name and phone fields come to the mail, the field with the name of the product remains empty ... Ajax transmits everything is fine, checked the debugger, why the php file does not process this field with the name of the product and emptiness comes to the mail?