Walmart review: expired visa

I have been out of the country and upon my return to the states i decided to put some money on my card while i was in Wal-Mart. I put $50.00 on the card #[protected]. I did not know at the time the card had expired. I figured since the system accepted the load that it was good. I tried to use the card at a later date and was told it said it was expired. How do i get my money back. The ST# is 0610 OP# [protected] TE# 11 TR# 05181 Debit Load 060538819035K REF#[protected] Network ID 0049 APPR CODE 054028 Loaded on04/06/11 $50.00 Call me soon and let me know what to do. Anthony Byrd