The best way to formally contact any higher official(in this case registrar) is to e-mail them first. 

E-Mail: registrar@aktu.ac.in                                                                                                                                                                                                   Phone: 0522 – 2771079

After emailing them, wait for 4-5 hours or a day if it's not an emergency and then try calling them so atleast you can say that you tried contacting them. You can also try at their help-desk within the restricted time:-

TOLL FREE Number   : 1800-180-0161 (10:00 AM to 5:00 PM)

Alternate Number       : 0522-2336800, 0522-2336811 (10:00 AM to 5:00 PM)

E-Mail                     : upsee.helpdesk@aktu.ac.in

I hope this clears your doubt and your issue gets resolved.

You can contact to UPSEE through mail i.e. upsee.helpdesk@aktu.ac.in   or you can contact them on this toll-free number 1800-180-0161 (10 AM - 5 PM) or on alternate numbers 0522-2336800,
0522-2336811
https://upsee.nic.in/publicinfo/Public/View.aspx?page=72