Hi @brian!
I get it now.
As you rightly say, you can't do anything with the contact.tpl which is a shame. It was as simple as creating custom fields that could appear on the form but well, it can't be done definitively.
Instead, I did it by creating the custom fields "phone" and "company" in the pre-sales department and editing the "supportticketsubmit-steptwo.tpl" file. I also removed the "attachment" field and the "upload" button.
Additionally, I disabled the select option for the priority field. It only shows as default option: "medium"; that way the customer cannot set any priority on the pre-sale ticket.
thanks for your reply!!