Medical Reimbursement Retroactive? Ex-wife is attempting to collect past 5+ years

[Father of 3]

What is the name of your state (only U.S. law)? Texas

My ex-wife is attempting to collect 5+ years worth of past medical reimbursement for the uninsured portion of medical visits. Per my decree, I'm required to pay 50% of out-of-pocket expenses not covered by insurance. I understand it and I agree with it. Here's the caveat: she's only provided me her out-of-pocket expenses one time, via email, and it was somewhat a copy-and-paste document from her bank account (or something). That was in November, 2011.

This is my decree wording:

"Reasonable and necessary health-care expenses not paid by insurance and incurred by or on behalf of a child" include, without limitation, any copayments for office visits or prescription drugs, the yearly deductible, if any, and medical, surgical, prescription drug, mental health-care services, dental, eye care, ophthalmological, and orthodontic charges. These reasonable and necessary health-care expenses do not include expenses for travel to and from the health-care provider or for nonprescription medication.

"Furnish" means:

a. to hand deliver the document by a person eighteen years of age or older either to the recipient or to a person who is eighteen years of age or older and permanently resides with the recipient;
b. to deliver the document to the recipient by certified mail, return receipt requested, to the recipient's last known mailing or residence address; or
c. to deliver the document to the recipient at the recipient's last known mailing or residence address using any person or entity whose principal business is that of a courier or deliverer of papers or documents either within or outside the United States.

Pursuant to section 154.183(c) of the Texas Family Code, the reasonable and necessary health-care expenses of the children that are not reimbursed by health insurance are allocated as follows: [ex-wife] is ORDERED to pay 50 percent and [ex-husband] is ORDERED to pay 50 percent of the unreimbursed health-care expenses if, at the time the expenses are incurred, [ex-wife] is providing health insurance as ordered.

The party who incurs a health-care expense on behalf of a child is ORDERED to submit to the other party all forms, receipts, bills, statements, and explanations of benefits reflecting the uninsured portion of the health-care expenses within thirty days after he or she receives them. The nonincurring party is ORDERED to pay his or her percentage of the uninsured portion of the health-care expenses either by paying the health-care provider directly or by reimbursing the incurring party for any advance payment exceeding the incurring party's percentage of the uninsured portion of the health-care expenses within thirty days after the nonincurring party receives the forms, receipts, bills, statements, and explanations of benefits.

Following my decree wording, my ex-wife never hand delivered, sent certified mail, or delivered to my home address any documents, receipts, forms, bills, statements, etc from any visit whatsoever. As I stated above, I only received one email from her with a document that had some expenses copied-and-pasted. As you can clearly see, emailing is not one of the options defined as "furnish." Also, the wording states the incurring party should send any bills, statements, etc, within thirty days received them.

I think she went to the State and gave them a bunch of receipts and now the State is coming after me for these expenses. Again, she never followed the decree wording within the time frame, manner in which to furnish the documents, and providing the actual bills, statements, etc needed.

Can the State of Texas collect based solely on her claim that she incurred these expenses and I never reimbursed her? She'll probably claim that all documents were hand delivered to me, which is 100% inaccurate.