After my initial review about presence of bots, SB came back and explained the situation. So I am going to give them benefit of doubt and continue using the site. Will update this again later based on the outcome.
I have so far purchased gift cards worth $2500. Only couple of times, it has happened that the cards partially used could no longer be used as the balance went to 0 (probably the seller used it). Raise has backed up their 100 day refund plan on both those occasions. Excellent customer service.