Hi student,

If you have paid fees for January and march Attempt of JEE Mains 2021 and you did not appear in the exam, your seat was left vacant at the center. This means that NTA has made all the necessary arrangements for you to give the exam but you haven't attempted that. Now, if you are willing to give the exam in May then, you are required to pay the fees again and that fees will not be considered.

Refer here for more info - JEE Main 2021 April Session - Registration, Syllabus, Pattern, Exam Date, Admit Card, Result, Score, Cutoff (careers360.com)

To check your chances in different colleges, you are required to use JEE Main College Predictor Tool:- https://engineering.careers360.com/jee-main-college-predictor?icn=QnA&ici=qna_answer

Feel free to ask doubts in the Comment Section.

I hope this information helps you.

Good Luck!