A program that grants points for using Bing search, which users can redeem for gift cards, sweepstakes entries, or charitable donations.
Just a follow up on this - I remembered I knew someone with quite high up contacts at MS. Got in touch with my friend (who also used to work at MS) and explained the farcical situation with Rewards 'customer service'. Lo and behold, I was able to redeem points within a day or 2 - but maybe it was just a coincidence!