I started learning on codechef from May 27,2025. I unlocked a premium session using credit point on May 27. For that I had received two premium credits on that day. After that I’ve been unlocking premium sessions using the credit points for the next three days for which I received 2 credit points each day. After that credit points had stopped from being creditted to me even though I am unlocking a premium session per day. So can you explain how it works??