Credits were added.
I am not giving free credits to recently opened account (last 3 months) or account with no activity.
You submitted 12 links so far on different dates (from 12/4 to 26/4). 10 are unique links (2 repeat).
2 links contain No-index tag. Out of remaining 8 links, 5 are indexed.
If you submit same links again, it will surely take your credit again as it goes again to the system for processing. Instead of submitting same links again, you need to wait 2 to 3 weeks to see best indexing rate.
It is temporarily unavailable for few days.
Instead of submitting all the links for processing together, some people prefer to process their links slowly in small batches in many days. People who have hundreds or thousands of links normally want them to process for indexing slowly in many days rather all together.