Amazon review: I have Amazon Prime but requested to pay shipping on a return.

On August 10 I purchased a Otherya 56" Roof Rack Cross Bar for $169.90 + tax = $195.39. Shortly after the purchase was made the price was reduced to $129.90 + tax (a $40.00 + tax reduction). I requested the $40.00 + tax reduction from Amazon and that was not possible. The other option was to return what was purchased and request a refund of $195.39 and then purchase the item at $129.90 + tax. When I attempted to return for a refund $195.39 I was advised that I had to pay $24.34 for shipping and my refund would be reduced to $171.05 despite that I had already paid for Amazon Prime ($113.85). Despite extra shipping expenses it has never been easily recognized by customers when items are purchased, and there is strong belief that having Amazon Prime that shipping overall is covered whenever required. Why is this an issue now? It can be noted that I have purchased a scattered item from Amazon over the years and this issue was never known until now and it can possibly have a negative impact on many customers.