A program that grants points for using Bing search, which users can redeem for gift cards, sweepstakes entries, or charitable donations.
Hii,
I understand your frustration, but it is not the case that items are "always" unavailable. The reality is that there is a limited number of codes allocated to each region. Because demand is very high, these codes run out quickly and take a considerable amount of time to be restocked.
This varies significantly from one region to another. For example, Robux codes tend to run out very quickly in most regions, and once they are gone, it takes a long time for them to become available again. This is why there is no set date for when these codes will return to stock; unfortunately, you will simply have to wait until they become available once more.
It is also worth noting that, since these codes come from external partners, restocking does not depend on Microsoft, but rather on the companies themselves—for instance, RPs come from Riot Games, Robux from Roblox, and so on.
(This is just my personal opinion.)
Please keep in mind that there is no official or fixed date for when codes are restocked in Microsoft Rewards.
Please consider providing feedback on this response (by accepting it or through another rating method), and feel free to visit the Microsoft Q&A community if you have any further questions.
Thanks.