A program that grants points for using Bing search, which users can redeem for gift cards, sweepstakes entries, or charitable donations.
I understand how frustrating it is when a popular reward like the 575 RP League of Legends code is unavailable for a long time.
This usually happens because Microsoft Rewards has a limited supply of digital codes from partners, and once they are claimed, the reward is removed until more codes are provided. There is no public restock schedule, and Microsoft typically does not announce when rewards will return, so due to high demand it can take days, weeks, or even more than a month before the option becomes available again.
I recommend checking your Redeem page regularly so you can be among the first to claim them once they become available.
As this is a user-to-user community forum, I’ll include the link to Microsoft Rewards support in case you need further information: https://rewards.bing.com/support