I rcvd a ticket for speeding in 2005, paid it w/a money order, now the county courthouse says i didn't pay.

I had to pay w/a money order because they didn't accept personal check or cash. However, I have moved two times since then and I can't find my money order receipt. Am I screwed? Now, they want me to pay the ticket again and fees for "failure to appear." Please list source after your answer.