Given the terrible exchange rate we get on shards, allow people to buy all characters. Set the price high for premium characters but being able to buy 3 shards a day is crazy. At least refresh along with the other shops in the game. I am sitting on more than 10,000 credits but can't use them. Also, you should provide an option to exchange rather than automatically exchanging all shards. Eventually players will need to collect more shard to upgrade characters further. We are going to feel ripped off when we were forced to,exchange them for useless credit in a store where there was nothing to buy.