Transcript Evaluation Services In The Us

Guys, I am applying to US grad schools. After  I sent photocopies of my transcript  to an evaluator in the USA, with an envelope i stole from school, they request original copies but it is to expensive for me .They sent this mail to me

"We cannot proceed with your case based on the copies submitted. If you do not want to make arrangements to submit a new transcript, then we will mail your transcript back to ****University for authentication. How would you like us to proceed?"

What then should I do, I am scared the school might say I Forged documents, or that is not authenticate. Anybody with similar experience?