I don't get this at all! 
You purchased a bundle at such an incredible sale price and because the product went on a lowers sale price  days later you want a refund?
This isn't DAZ as far as I know and I am amazed by your request.
By your way of thinking, if you had bought the product 28 days earlier at full price, you would expect a refund also?
It is very good of Rena to accept your request that's all I can say.