Amazon Canceled My Discounted Order Without Notice and Now the Price Has Increased

I just ordered something on Amazon that was on sale, but they canceled it without telling me first. I noticed that the price went up a lot when I tried to reorder. I reached out to customer service, and they told me, "There is nothing to do," which is just not okay. I thought Amazon would do better than this. I just don’t get why my original order got canceled, especially since I didn’t hear anything about it. I need to get this issue sorted out right away, so I'm going to file a formal complaint with the Consumer Arbitration Committee today. I'm really disappointed with this situation since it's my first time facing an issue like this on Amazon.