Amazon's Unreliable Prime Discount and Price Manipulation

I signed up for Amazon Prime so I could take advantage of a sale and buy a TV. But when I put the TV in my shopping cart, I couldn't use my Maximum card to get the 500 TL discount like it said I could. Not only that, but the promotional price of the TV was raised from 17,999 TL to around 18,500 TL and then to around 19,500 TL until the end of Prime discount day. What kind of crazy is this? How does this campaign work? I believe you have deceived me. I didn't join Prime so that people would treat me like a joke. You're supposed to be a big business with a good name. Shame on you!