Walmart review: false advertisement of $5 credit

Walmart advertised, of which I have kept, June 2014 two offers on a green and orange rectangle " Get a $5 statement credit when you make purchases totaling $25 or more in-store at Walmart with your Walmart credit card. Now through July 15, 2014.

After that ad appeared I went and shopped at Walmart #1086 on two occasions: June 22 and 29, 2014. Both days were after the ad appeared and before July 15, 2014. Both times my total purchases were over $25 (they were $53.80 and $52.46 respectively), both shopping trips were in-store and both were using my Walmart credit card.
I have never received either of my expected $5 statement credits.
I have sent Walmart four different emails saying the same, via Walmart.com.
Today I received my first and only response.
The reply incorrectly promised me that when I 'made the purchase at the gas pump I would get the discount".
?
Obviously it is a form letter, and obviously somebody pushed the wrong form letter button, and obviously he/she did not even read my messages which were as precise and clear as this one.
Can you help? My name is Laura M. Mathers, 1801 Michigan Avenue, #H-1, Saint Cloud, Florida 34769 Telephone [protected] Email: [protected]@yahoo.com The Walmart store is #1086 located in Saint Cloud, Florida 34769.