Supplier Price Hike

During the month of July 2023 Takealot issued me with a R150.00 voucher, minimum spend amount R550.00. On the 20th of July 2023 I utilized the R150.00 voucher towards order number ***. One of the items in the order was a rubber rake at R197.00. On the 2nd of August 2023 the rake was cancelled due to the supplier not having any stock. Takealot then gave me a credit of R47.00 and the full amount of the voucher was used for the item that I did not receive. The item is available to order on Takealot, but at a higher price of R220.00. I have since order and paid for the rake at the higher price. I expect Takealot to refund me the full voucher amount as well. Why must I forfeit the voucher when the supplier clearly wants to sell the item at a higher price