BRO . I HAVE ALSO PAID FEE ONLINE ONLY .ALL ARE SAYING GO TO CET OFFICE AND ALL . I WILL TELL U SIMPLE THING AND YOUR PROBLEM WILL BE SOLVED . YOU MUST HAVE PRINTED YOUR ONLINE APPLICATION WHICH IS OF 4-5 PAGES . AT THE END YOU WILL SEE PAYMENT STATUS COLUMN . SO THATS YOUR PAYMENT CHALLAN . THANKS ME LATER AND DONT BE TENSED NOW . AND DONT LISTEN TO OTHERS WHO ARE MAKING YOU MORE TENSED .

ANSWER BY :-MOHAK (MAD ENGINEER) :p 

dear student 

you can complaint through mail to the examination authority 

  keauthority-ka@nic.in

or

kea@karnataka.gov.in

Helpline Number - 080-23460460 (5 Lines) between 9.30 am and 6.00 pm on all working days.