Hi, 

This is the reference contact mail :  jeemain-nta@nic.in

You can contact them anytime.also if you insist jeemain.in, you'll find contact us window where you can find their contact number too 

Hope it helps

Good luck

You can contact JEE MAIN sending a mail to the following id

 jeemain-nta[at]nic[dot]in

You can know the complete details of contact including telephone number send other email writing by visiting official website or just visit the link given below

https://jeemain.nic.in/WebInfo/Public/View.aspx?page=80