Same thing also happened to me on 07/02/2020 I have paid my application fee but it showing unpaid I also have downloaded my confirmation page but it is not updated on my application page

Hey there

In case you have done multiple paymensts do not get panic write to your bank regarding the issue and if possible call the costomer service if possible. The money paid multiple times get refunded within 24 hours usually depending upon your bank.

Check about JEE main

https://www.google.com/url?sa=t&source=web&rct=j&url=https://engineering.careers360.com/articles/jee-main-application-form/amp&ved=2ahUKEwjm5Yqy0sjkAhWVUn0KHVWNDUMQFjABegQIDRAI&usg=AOvVaw3MLE7YdM3hAO7IErzAG_F9&ampcf=1

Good luck