I want to print all the items from a .txt file using a IDictionary to store them but the program prints just the last values for each id from 1-24

Question

So I have a .txt file with the following entities

1,1,10,PARTICIPANT
2,1,15,PARTICIPANT
3,1,8,PARTICIPANT
4,1,20,PARTICIPANT
5,1,30,PARTICIPANT
6,1,7,REZERVA